
Class. 
Book- 



COPYRIGHT DEPOSIT 



^ \ 



AIDS 



Engineers' Examinations 



QUESTIONS AND ANSWERS. 



y 



A 



Copyright by 

THEO. AUDEL & CO., New York City. 

Sept., 1894 and Sept., 1901 



T 



K 



This work is Dedicated ro 
VICTOR HAWKINS 

AT WHOSE REQUEST IT HAS BEEN COMPILED, 



^ 7^ 



/ 




WASHINGTON MULLIN. 
See page 203. 



^ 



•7 






TO 

Engineers' Examinations. 

PREPARED FOR 

APPLICANTS OF ALL GRADES, 

WITH 

QUESTIONS AND ANSWERS. 

A Summav'tf of tlie Principles and Practice 
of Steam Engineering, 




By N. HAWKINS, M. E., 

Author: New Catechism of the Steam Engine: Hand Booh 

of Calculations for Engineers; Instructions for the 

Boiler Room ; New Catechism of Electricity, etc. 



New York: 
Theo. Audel & Co., 63 Fifth Ave. 



X 



1902. i ^ ' 




-^'/^/Ji 



z 



\ 



INTRODUCTION. 



Chere are three parties to an engineer's licenfir 

First. The Applicant. 

Second The Public. 

Third The Examiners, or examining board of engineers. 

To the applicant the period cf an examination is a season 
of nervous dread and the utmost fitness does not always 
remove the feeling of anxiety. 

Men often operate steam plants satisfactorily who can- 
not tell how they do it, and a thoroughly practical engineer 
may make a very poor showing when questioned by an 
examiner. 

it is sometimes still worse when modest applicants 
are required to write their experience, for in the hands of 
many men the pen is an awkward tool ; hence a very large 
margin is allowed to men who can demonstrate that they 
have had the necessary practical experience, even though 
they may not be able to answer questions oif -hand ; and those 
who have become " rattled " under the unusual catechising. 
are frequently kindly advised by the examiner to " come and 
try a^ain." 



V 



K 



V 



z 



£NTRODUCnOJS. 



WTiile the tendency in all lines of engineering is toward 
thorough familiarity with principles, there are stiU good 
chances for safe men, who are comparatively unlearned, to 
acquire experience by actual work in engine rooms. 

The relation of the public, to the issue of an engineer's 
license, is the same as that in which it stands to the issue of 
druggists and drug-clerk Ucenses ; that is, the fundamental 
right to protect itself from the criminal ignorance of un- 
worthy pretenders in handling or dispensing dangerous ma- 
terials. 

The community possesses the privilege of passing upon 
the qualifications of its citizens who propose to manage 
and control machinery or chemicals which, used without 
experience or good natural judgment, are liable to cause 
suffering and loss to innocent persona. 

No one now disputes this fundamental principle of common 
law ; and it is a notable fact that the more competent a man 
is for the performance of an engineer's duties, the more he 
desires an honest administration of the laws regarding the 
subject, and a safe standard of qualification- 
Relating to the office of an Examining Engineer it may be 
said that the position is no sinecure, for he should be 
thoroughly qualified to examine and pass on candidates, so 
that none but sober, competent and careful men are passed. 
As examinations must, perforce, be conducted by practical 
engineers, it follows that upon engineers, as a class and pro 
fession, depend their own standing in the community. If 
the Examiner is a high-toned, sober, intelligent man, in the 
course of time the men he passes upon, and to whom he 
awards licenses, will be very nearly up to his own standard as 



K 7 



/- 



X 



INTBODUCTION 



a man. It would be worthy of interest to know the history, 
education and experience of, say, one hundred of the exam- 
ining engineers of the country ; for these men, as models, the 
thousands of men who come under their contact, will cer- 
tainly emulate and approach while never passing their 
standard of excellence; hence the future welfare of steam 
engineering as a profession and the money income of its 
members depend almost wholly upon the Examiners. 

The test to which Examiners themselves are put before 
receiving their appointments is very se'^<^re. and to have held 
this appointment is a life-long honor. 

In a recent single year's report of the New York City 
Steam Boiler Inspection and Engineer Bureau, there were 
one thousand one hundred and sixteen examinations of new 
applicants for engineer's licenses, of which no less than five 
hundred and thirty were found incompetent and certificates 
refused. 

Of the five hundred and eighty-six successful applicants, 
there passed; 

On the first examination 434 

On the second examination 126 

On tlie third examination. . . 23 

On the fourth examination 8 

586 

la the same year there were: 

Certificates, renewed 4. 597 

" transferred I,3d3 

New certificates granted 586 

Making the total number in force. . 6,566 



\: 



7 



/ 



mTRODVVTlOIs. 



These six thousand five hundred and sixty -six certificatee 
were divided thus 

Certificates of the 1st class 1, 83^ 

2d class 1,49b 

3d class, a. 409 

Vhe department engineers. 196 

Permits for boilers only ............ 135 

6.566 

and in ihe same year there were eight thousand four 
Hundred and thirty eight inspections made of steam boilers. 

The sum of two dollars for each certificate, amounting to 
$13,724.00 was collected and paid to the Treasurer of the 
Police Pension Fund in accordance with the provisions of 
Chap. 437, Laws of 1885. 

In New York City each boiler is numbered in tlie Records 
at Headquarters ; each Engineer's certificate is likewise num- 
bered, and a heavy fine is imposed for misusing the papers 
for another's benefit ; and in case of the loss even of the 
papers the fact must be immediately reported at the office of 
the Examiner, and a fine may be imposed for the carelessness 
which resulted in the loss of the certificate. 

It will tlius appear that each license applies to a special 
steam-plant, of which a full description is kept in the files. 
When an engineer changes his position he must have his 
certificate "transferred." By this it will be seen that an 
applicant must first secure his position ; and then his license 
— if he is found worthy — is usually granted upon the written 
request of the owner of the steam-plant, who has previously 
engaged him, ajid fijted the details of service and compensa 

tiOTl 

^^ / 



/ \ 



INTRODUCTION, 



The certificates are for one year, and on each are printed 
the following rules : 

" Holders of certificates must apply to the officer in com 
mand of the Sanitary Company for re-examination and re 
aewal of certificates on the dates of the expiration of the 
certificate. This date of expiration will be found printed on 
the face of the certificate. 

The certificate allows the person named to take charge of 
and operate the steam-boiler mentioned, bid no other, and 
will be revoked on proo^ of uegliseuce or insobriety." 



V 



-7 



/ 



MIDS 

TO 

ENGINEERS' EXAMINATIONS. 



The necessary qualifications to secure a license are nearly 
in the following order : 

1st. — Character or general fitness for the trust. 

2d. — Knowledge and experience relating to the steam 
generator. 

3d. — Skill in the running of the steam-engine and other 
machines. 

Before the issue or the refusal of a license to an applicant 
he is examined personally, and alone, by one of the Board, 
all of whom are practical engineers ; and there is no stated 
list of questions either oral or written. 

If a candidate show^s by his answers that he is familiar, 
through actual experience with his duties, and not coached 
by some one for the mere purpose of obtaining a license, be 
is entitled to his papers. 

Relating to character qualification, it may be said that 
as the engineer is to be in charge with an almost independ 



li /SNOINWEBS' lijJi^MlJ\A.TIOJSli. 



ent trust of property and life, the Examiner will, before any- 
thing else, seek to ascertain something of the habits and 
moral principles of the applicant. No man, if it is known, 
who ever yields to intoxication, and no one who is a con- 
victed embezzler, will be granted a license ; without question 
the indefinable marks of an honest man go very far towards 
securing to him his papers. 

The reliable engineer is nearly always a man of thoughtf ui 
dignity of manners, as naturally becomes habitual to one under 
an vmceasing weight of responsibility, involving so much; 
this outward evidence of inward qualities is rightly most 
tavorable to an applicant. 

Character is what a man really is, and a good character 
implies many virtues, such as truthfulness, courage and cool- 
ness under sudden danger, a habit of tidiness in person and 
dress, strict honesty and large-mindedness ; all these are to 
be expected from an applicant for an engineer's papers. 

So important is this qualification — of good character — con 
fiidered, that there are printed on each of the seven thonsand 
licenses issued by New York City the following. 

Chapter 643, Laws of 1886. •' When, on examination of 
an applicant, it appears to the satisfaction of the Engineers 
that he lacks natural capacity, or mechanicel skUl, knowl- 
edge or experience; or is unfitted by habits of insobriety to 
perform the required duties in a manner consistent with 
safety of life, a certificate of qualification will be denied. 
Renewals of certificates will be refused, and certificates wiD 
be revoked on proof of like deficiencies." 

For many reasons a good character is the first requisite far 
the STuarlDs; of a license, nomine even before sJdU souj 



ENOTXEERS' EXAMINATIONS, 15 

knowledge of the business. It is on account of its relative 
importance that applicants are first required to give an ac- 
count of their experience in the practical duties of engineer, 
macliinist or firemen. 

As to the general fitness of the applicant it may be said 
chat age implying a certain length of experience is necessary ; 
svhile on the other, extreme age, even with great skillful 
aeps if accompanied by bodily weakness, is a bar to passing, 
Defective eyesight, an evidence of extreme nervousness, and 
certain bo<lily defects, are very potent reasons for withhold 
ing consent 

Secondly, the examiner will proceed to ascertain the 
applicant's kno vledge of the steam generator. No applicant 
wanting in praccical experience in the care and management 
of the steam boiler will be permitted to pass. If there were no 
liabU ity of steam explosions there would be no need of issuing 
licenses in stationary engineering service any more than 
for a license to run wood or iron working machinery, pile 
drivers, or the thousand and one machines used in modern 
industry for example, no license is required to run a water- 
mill liowever large, unless it has a steam boiler on tht= 
prewises 

Accidents m steam plants, like the bursting of fly-wheels 
and breaking of cylinder -heads, even if accompanied by in 
jury and loss of life, cause no uneasiness in the public mind, 
and carry no personal discredit to the Examiner; but. if a 
license is granted to an unworthy person, and an explosion 
of a steam boiler occurs, causing personal injury or loss of 
life, then the public, through its Coroner's or other juries will 



le ENGINEERS' EXAMINATIONS. 

blame the Examiner for being remiss in guarding its safety, 
as well as the person in direct charge. Hence, the sharpest 
questionings come in reference to the steam boiler. 

While the first element of stress is laid upon character, 
the second is properly put upon the knowledge of the steam 
generator, and the greater portion of this book of ' ' aids " 
will be devoted to the problems relating to its construction, 
safety and management. 

Third will come all these questions relating to the steam-sn- 
gine, pumps, piping and general knowledge, which go to prove 
that the applicant is really an engineer (that is, an ingenious 
person), capable of the position of trust to which he aspires. 

So very different in responsibility are the positions required 
to be filled by the engineer that it is almost always a matter 
of individual judgment with the examiner as to the fitness 
of the man for the place ; and in forming this judgment 
and deciding aright both the discernment and skUl of the 
examining engineer are exhibited. 

In the latter part of this work will be found several ex- 
tracts from city and United States laws, relating to engineer's 
licenses and examinations. These will, doubtless, form 
models for other parts of the country, as yet without laws 
bearing on the subject, as they, one by one, adopt the systeui 
of protection found so useful, where it has been tested 



CLASSIFICATION OF KNOWLEDGE. 17 



CLASSIFICATION OF KNOWLEDGE THE KEY 
TO SUCCESS. 



" When a 'mizn''s knowledge is not in order the more he has of it the 
■77orse he is o^."— OiD Proverb. 

This old saying conveys the strange truth that sometimes 
the mors a man knows the more useless is what he knows. 
It is. true notwithstanding its strangeness, and it is true 
especially in practical steam engineering. 

On a certain corner in the Bowery of New York City may 
be seen a store window packed full of all kinds of cutlery — 
razors, corkscrews, butcher knives, files, screw drivers, 
pistols, hammers, boxes of drawing tools and a hundred 
other things in the hardware line. These are all in one jum- 
bled mass in indescribable confusion and are an emblem of 
the disorder in the mind of an unapt, blundering, unskillful 
man in the engine or boiler room. He has the knowledge, 
perhaps, but it is never available when needed. 

Now, on Park Row, a little south, there is a regular hard- 
w^are store with a stock of goods a hundred times the variety 
and a thousand times as large as that in the Bowery and yet 
scores of men and many teams serve hundreds of customers 
every day ancf block the sidewalks with the incoming and 
outgoing loads of their ware, handled in the big many 



18 CLASSIFICATION OF KNOWLEDGE. 

storied building and all without confusion, loss or hurry. 
This is also a symbol of another kind of man who has his 
wide and extensive knowledge well in hand for ready use, 
who easily may assume with credit the position of cliief 
engineer. 

What is the key to success in the management of a steam 
plant and of personal advancement ? It consists in the 
scientific or orderly arrangement of the various knowledge 
required to make the experienced engineer. 

Not only the chief but the assistant engineer, the oiler and 
the fireman should strive towards this due classification — as 
soon as a fact is acquired let it be stored away in its proper 
place in the mind. Facts about steam with the steam 
(mental) department — facts about the engine in the engine 
(mental) department ; facts about piping and valves with the 
pipe and valve (mental) department, etc. , etc. 

In this way the mind and memory are filled with available 
knov.dedge like a well written book with a reference index. 

For instance all the various items of information relating 
to the physical properties of steam should be grouped together 
in the engineer's mind, or he should know where and when 
to lay his hands upon needed information relating to this 
subject. Example: There is a table of steam properties 
called Regnault's Tables, which show the temperature of 
steam at the different pressures, the volume per pound in 
cubic feet at the different temperatures, etc. Now it is not 
necessary to carry all the figures in one's ihtnd, it is only 
necessary to know of the existence of the Tables, where they 



CLASSIFICATION OF KNOWLEDGE. 19 

are to be found — in what book and in what library, and finally 
to accurately apply the figures to the problem to be decided. 

To know these and other fundamental laws is a long step 
in the science of steam engineering and the remuneration is 
large to the man who knows and can use his knowledge. 

The rudiments of steam engineering can be acquired by 
about two years of constant application, and close observation, 
by a person who has a liking for the work. A person w^ho 
does not like to perform the duties required will never acquire 
"full competency" for the duties required of a chief engi 
neer, for the reason that he will not have the opportunity. 

A system of education that tends to broaden the mind and 
thus render it capable of dealing confidently with large 
questions is not only most likely to make the engineer edu- 
cated uiider it more respected by those with whom he comes 
into contact in professional life, but it gives him a wider 
range of opportunities. 

The immense magnitude of modern steam plants and their 
combination of Steam, Electricity, Refrigeration, Transpor- 
tation, etc. , calls for first class men to manage the complex 
machinery. 

This theme is a difficult although necessary one, and 
etdvice relating to it may be summed up thus — 

First. Do not "lumber " the mind with useless matters. 

Second. Be sure of the truth of each single fact. 

Third. Store the fact or item of information away in the 
mind with other kindred items relating to the same depart 
naent of engineering. 



20 CLASSIFICATION OF KNOWLEDGE, 

To make the most of oneself is a problem, which has been 
answered by the word concentration. Keep close to one line 
of advancement and be content to be ignorant of some things 
in order to know thoroughly some others, The path being 
chosen, then let the advance be persistent and unceasing. It 
was thus that Stephenson produced such results in locomo 
tion, and Watt such wonders with the steam engine. 

This persistent industry is not irksome. It carries its own 
reward, and the resvilts are definite and sure. 

" One step and then another. 

And the longest walk is ended ; 
One stitch and then another. 

And the largest rent is mended. 
One brick upon another. 

And the highest wall is made : 
One flake upon another. 

And the deepest snow is laid. 



THE STEAM BOILER. 21 



THE STEAM BOILER. 



WMle the shapes and forms in which steam generators 
have been constructed are many, they all agree in one point 
— they are closed vessels strongly made so as to withstand an 
internal pressure of considerable force. 

In engineering terms this force is called the steam press- 
ure and it varies from 5 to 300 lbs. per square inch. It is the 
first rule in the design of steam boilers to provide against 
this varying internal force. 

While the sphere is the stromjest form of vessel to resist 
internal pressure, there are many practical reasons which 
prevent its being used for the purpose. Next to the sphere 
the cylindrical form is the simplest and strongest, and is now 
universally adopted. 

The steam boiler has two essential parts, the furnace 
which contains the fuel to be burnt and the boiler containing 
the water to be evaporated. Within the boiler there nmst be 
steam-room as well as water space — outside there must be 
heating surface and a chimney or other apparatus to convej' 
away the waste products of combustion. 



22 ENOINEEBS' EXAMJ]VATLL\NB 



Questions and Answers Relating to Materials 
for Boilers. 

Ques. What is the meaning of Tensile strength when ap 
plied to rivets, braces and boiler plates ? 

Ans. It is that amount of force— usually ex- 
pressed in pounds — which, steadily and slowly ap- 
plied in a, straight line, just overcomes the cohesion 
of the particles and pulls it into separate parts 

Ques. What is the meaning of shearing strength ? 

Ans. It is that amount of force — usually ex- 
pressed in pounds — which, if steadily and slowly 
applied to the rivet, at right angles to its axis, causes 
it to separate in parts, which slide over each other. 
This separation is nearly always at right angles, and 
in common language is called "shearing off the 
the rivets." 

(Jues. What is the meaning of elastic limit ? 

Ans. This is the point to which steel or iron can 
be stretched out, and from which the metal will 
return to its original position. When steel is pulled 
beyond its limit of elasticity, it does not return to 
its old place ; the "bagging" of a burnt sheet over 
the fire is an example of the plate having been 
Stretched beyond iis limit of return. 



QUESTIONS AND ANSWERS. *23 

Ques. What is the meaning of ductile ? 

Ans. The material is " ductile/' when it can be 
extended by a pulling or tensile force and remain 
extended after the force is removed ; the greater 
the permanent extension the more ductile the ma- 
terial. 

(Jues What is the meaning of " tough " when applied to 
iron or steel ? 

Ans. The material is said to be tough when it 
can be bent first in one direction and then the op- 
posite direction without breaking or cracking. The 
greater the angles it bends through (coupled with the 
number of times it bends) the tougher it is. 

Ques. What is the meaning of malleable ? 

Ans. This is the term applied to iron or steel 
when it can be extended by hammering or rolling 
without cracking and remain extended ; the more it 
can be extended without fracturing, the more malle- 
able it is. 

Ques. What is weldable iron or steel ? 

Ans. This is the term which is applied to the 
material if it can be united when hot by hammering 
or pressing together the heated parts. The nearer 
the properties of the metal after being welded are 
to what they were before being heated and welded, 
the more weldable it is. 

Ques. What does homogeneous mean when applied to 
boiler plates ? 



84 ENOmEEBS' EXAMINATIONS. 

Ans. This word describes material of the same 
structure and nature ; where the grain or fibre of 
the plate is the same in every direction. 

Ques. What is the meaning of cold-short iron or steel ? 

Ans. This is a name given to the material when 
it cannot be rolled or hammered, or be bent when 
cold without cracking; such a material can be worked 
or bent when at a great heat, but not at any tem- 
perature greater than that assigned to dull-red. 

Ques. What is the meaning of " hot -short ?" 

Ans. This is when the material cannot be easily 
worked under the hammer, or by rolling at a red- 
heat, at any temperature which is assigned to a red 
heat, without fracturing or cracking, such a material 
may be worked or bent at a less heat. 

Ques. What is the meaning of elongation of metals ? 

Ans. The amount of stretching usually expressed 
in lbs. which a test piece will bear, due to a steady 
and slowly applied force before it is pulled into 
parts. 

Ques. Describe the qualities which should be possessed by 

a good boiler-plate ? 

Ans. The plate should not be too large, and 
should have been satisfactorily tested at the mill 
by suitable bending tests, and by the testing ma- 
chine, each sheet being marked with the maker's 
name, with the figures showing what tensile 
Strength it had stood in the test. 



QUESTIONS AND ANSfVEUS. 23 



Ques. Repeat the answer, using the definitions for boiler 
materials in their proper places ? 

Ans. The material should be homogeneous^ and of 
suitable tensile strength and elongation, best suited for 
the purpose, having an elastic limit that will ensure 
ihe boilei" being reliable ; it should be tough and 
ductile ; the material should be inalleable, and in some 
cases weldable ; that which is of a decidedly cold- 
short or hot-short nature should be avoided. 

Ques. What is steel ? 

Ans. Steel is iron with a mixture of carbon or 
an alloy of iron — the alloy being principally carbon 
steel ; can be melted like cast iron and welded like 
wrought iron. There are hard and soft steels, 
according to the process of production and propor- 
tion of alloy. 

Ques. What is iron ? 

Ans. It is one of the original substances of which 
the globe is composed. There is very little pure 
iron, it being nearly always found combined with 
other things. Wrought iron is iron with the impur- 
ities worked (or wrought out) and thus rendered 
soft and malleable, ready to be beaten by the ham- 
mer into any desired form or rolled into thin plate.* 

Qnes. What is the tensile strength of steel and iron ? 

Ans Of iron according to the table, 50,000 to 
the square inch average — of steel about 70,000 lbs 



* NoTB. A bar of Iron worth $5.00, It Is stated, is worth $10.50 when inadeln*j0 
horseshoes, $55.00 in the form of needles, $3,285 in peiiknlle bljules, $i9,480 iD 
shirt buttons, and $250,000 In balance springs of watches. 



26 ENaiNEEBS' EXAMINATIONS. 

Ques. What is the difference between steel and iron ? 

Ans. The steel in ordinary use is an alloy of iron 
which is cast while in a fluid state into a malleable 
ingot. To be steel it must be malleable and the 
product of melting or fusion. This definition 
excludes pig-iron which is fused or melted, but not 
malleable; and wrought iron which is malleable but 
not fused or melted. 

Ques. What is an alloy, define it ? 

Ans. An alloy is a mixture or compound of two 
or more metals. Ex.: two parts of tin and six parts 
of lead is " an alloy " suitable for fusible plugs and 
which melts at 380° fahrenheit. To alloy is usually 
to reduce the quality of one of the parts, and the 
least valuable is sometimes called "an alloy." 



Questions and Answers Relating to the Ex- 
pansion and Contraction of Steam Boilers. 

(^ues. When a boiler is in use what is the effect of heatii."< 
and cooling it ? 

Ans. The heat expands and enlarges the whole 
structure, and it should be so constructed and set in 
the brick work, that this change in form may be as 
uniform as possible — one part equally with another. 

(Jiies. Does the cold contract the boiler ? 

Ans. Yes, and the process of enlarging and con- 
tracting is a continual process, as long as the boiler 
is making steam. 



QUESTIONS AND ANSWERS. 27 

Ques. What is the effect of unequal expansion and con- 
traction ? 

Ans. It is a severe test of the strength of the 
boiler, the tubes or flues expanding lengthwise with 
a force sufficient to tear the heads out of the boiler. 

The smaller the proportion of the surface of a 
boiler that is exposed to the heat, the more active 
will be the effect of the expanding and contracting 
forces, and in the case of boilers, set more than 
half exposed to the influence of the atmosphere, the 
power exercised by the expansive heat of the fire 
below and the contraction due to the low tempera- 
ture above, are almost enough to tear the boiler to 
pieces. 

Ques. Is any more to be said upon this ? 

Ans. It is the unequal expansion of the shell and 
tubes that really does more injury to a steam boiler 
than the expansion and contraction due to changes 
in the pressure of steam ; the leakage and cases of 
rupture that so often occur in the lower seams and 
along the bottom of horizontally fired boilers are 
unquestionably due to these causes; in very many 
instances forced firing in getting up steam on first 
starting the boiler is to blame. 

Ques. Is the force of expansion and contraction known sc 
that it can be "nearly " calculated ? 

Ans. Yes, iron will exert a strain of 150 pounds 
per square inch for every degree of temperature. 
Suppose iron has been heated to 350 degrees and 



28 ENGINEERS' EXAMINATIONS. 

cooled down to 60 degrees ; if it is securely riveted 
or otherwise fastened it will be cooled 350° — 60°= 
290° X 150 =^44,500=221^ tons, on every square 
inch of section. 

Ques. Name an instance where this force is likely to be 

langerously exerted ? 

Ans. Where the tubes are placed very near the 
bottom of a boiler, in which case the pressure is all 
on the lower side of the heads and the plates that 
keep them together ; it is not unusual for these 
plates to be ruptured or the seams sprung under- 
neath, causing troublesome and often dangerous 
leaks. 

Ques. How are these difficulties to be avoided ? 

Ans. To avoid the injuries so often caused to 
boilers in this manner, it is necessary, therefore, to 
exercise great care in raising steam in new boilers 
or those that have been blown out and allowed to 
cool down. The fire should be raised moderately 
and gradually, and the boiler moderately filled with 
water, so that the increase in the temperature may 
be gradual. In cooling off a boiler the same care 
must be exercised ; nor should the furnace doors be 
suddenly thrown open or any other proceeding 
taken that will result in suddenly lowering the boiler 
temperature, a rapid decrease in the heat being quite 
as bad for the safety and durability of the boiler as 
the immoderate and unequal increase above referred 
to. 



ENGINEER'S EXAMINATIONS. 28 



BOILER BRACES AND STAYS. 



Portions of boiler shells which are flat, or which otherwise 
deviate from the round or egg shape, are necessarily strength 
ened by means of stays or braces, against the enormous 
outward pressure caused by the steam. 

The only forms for the shell of boilers which are safe 
against bursting by internal pressure, without the aid of 
stays, are the cylinder and the sphere or egg shape. 

The tubes which extend from end to end of the tubular 
boiler, it has been proved, furnish sufficient holding power to 
amply stay the jiart of the head to which they are attached 
and also two inches above the upper row of tubes. 

The flanges of the head being securely united to the shell, 
and being also curved or dished, it may likewise be safely 
assumed that no braces need be provided for that part of the 
head which lies within three (3) inches of the shell. 

The part of a horizontal tubular boiler which needs to be 
braced therefore consists of a segment of a circle whose 
circumference lies three inches within the circle of the shell 
and whose base is two inches above the upper row of tubes. 

Thus in a 6-foot boiler, whose upjier row of tubes is 26 
belo"w the top of the shell, the part of the head which requires 
bracing consists in a segment of a circle, the diameter of 



30 QUESTIONS AND ANSWERS. 

which is 60 inches and the heighth of which is 21 inches ; 21 
inches being the measured heighth, 26 inches less the 3 
inches supported by the flange and the 2 inches supported by 
the flues. 

Each square inch of this flat surface must be practically 
supported by the braces, owing to the thinness of the plates, 
of which the boiler heads are constructed ; and large allow- 
ance must be made for weakening caused by the age and use 
of the boiler. 



Questions and Answers Relating to Boiler 
Braces and Stays. 

Ques. What are some of the names of boiler braces and 

stays ? 

Ans. Crowfoot-brace, jaw-brace, head-to-head- 
brace or through braces, gusset-stay. 

Ques. What are through braces ? 

Ans. The same as head-to-head braces, /. <?,, they 
pass from one end of the boiler to another. 

(|ues. What is the crowfoot brace ? 

Ans. This is sometimes called the "solid brace" 
because it is made of one piece of iron with both 
ends " flanged out " for the purpose of riveting to 
both the shell and head. 

Ques. What are radial braces ? 



ENOINEEBS' EXAMINATIONS. 



SI 



Ans. These include the crowfoot and braces 
attached to T iron, and so placed as to run back to 
the shell in a direct line from the head fastening, at 
a proper angle. 




Ques. What is the difficult problem in arranging the 
braces inside a steam boiler ? 

Ans. It is of allowing access to the boiler for 
examination and still to properly arrange the braces 
so that each shall bear its due proportion of load. 

(Jues. Of what material should braces be made ? 

Ans. Of the best iron, without weld, and should 
be, where threaded, upset for six or eight inches 
from the ends, so that when these ends are threaded 
the diameter at the bottom of the thread shall 
slightly exceed the diameter of the brace.* 

* With radial bracing greater strength is obtained by increasing 
the number of the braces. With through braces, on tlie other hand, 
increased pressure is provided for by an increase in the size of the 
braces. This is an iicportant consideration ; for braces that at 100 
^)ounds pressure sustain a stress of 7,500 pounds per square inch, would 
not be proper if the boiler were to carry 125 or 1.50 pounds. The braces 
should always be proportioned to the surface they have to sustain, 
and to the pressure of the steam. It may seem needless to refer to so 
obvious a fact as this, but our experience has shown that too little 
attention is sometimes paid to it, and hence we feel called upon to 
urge its importance.— T7i6 Locomotive, Feby., 1S9U. 



82 



QUESTIONS AND ANSWERS. 



Ques. What stress is allowed on boiler stays ? 

Ans. The greatest stress to which a boiler sta)^ 
should be exposed is 6,000 lbs. per square inch of 
section* at smallest part of stay if made of iron and 
but little more if made of unwelded steel. 



Qiies. How do you find the absolute stress or strain on the 
flat surface of a steam boiler, which is carried by the stays 1 

Ans. Choose 
three stays at three ^ 
corners of a 
square — multiply 
the sides in inches 
and the result is 
the number of 
square inches of 
surface depend- 
ing upon one bolt 
or stay for sup- 
porting strength. 

Qnes. Give an example. 

Ans. Suppose the stays measure 5 inches from 
center to center each way with steam at 60 lbs., 
then : 

5X5 = 25X60= 1,500 lbs. borne by i stay.f 




* This is the U. S. Government rule— iV to A the tensile strength 
of the iron or steel used for hraces is a safe rule to follow. Many 
State and City Ordinances allow 7,500 lbs. net stress. 

+ The cut exhibits more clearly the process. Measure the distance 
from A to B in inches and from A to C. Multiply by steam pressure. 



ENGINEERS EXAMINATIONS. »3 



Ques. How do you ascertain the number and size of the 
stay bolts to be used on a flat surface in a boiler ? 

Ans. By finding the total pressure on the unsup- 
ported portion and dividing it by the lumber of 
stays, each of which should be strong enough to 
bear its proportion* 

Ques. In examining the interior of the boiler, which should 
be done periodically, what are some of the defects for which 
you would be on the lookout ? 

Ans. For slack braces, for pins missing from the 
braces, and also to see that none of the^races have 
more than their due share of strain, and for leaky 
socket-bolts. 

Qiies. What else would you particularly look for ? 

Ans. For defective riveting, defective heads to 
the rivets, and for broken and loose stays and braces. 

CJues. When defects are found who is the best party to 
make the repairs ? 

Ans. An experienced boiler maker. 

(Jues. If no good boUer maker was available what would 

you do then ? 

Ans. I would run no risk but wait until one 
could be had — unless I myself was capable of mak- 
ing a temporary repair, and then I would try and 
prove myself an engineer worthy of my position. 



* The stays should be well fitted and each one carefully tightened 
and as far as possible each sta y in a group should have the same reg-- 
nlar strain upon it. 



84 ENGINTSERS' EXjLMJN^TIOXS. 

Ques. When a new boiler is put into service and it begins 
to exhibit signs of distress and leakage after being fired up 
for ii few days or weeks, what is usually the cause ? 

Ans. It is probably the effect of overstraining, 

Ques. What is the cause of tliis ? 

Ans. Frequently the end plates are too thick or 
too rigidly stayed, thus preventing the plate from 
slightly yielding or "breathing" in sympathy with 
the lengthening and shortening of the flue tubes, 
constantly taking place with each variation of tem- 
perature. 

Ques. VTiat remedy is there for this ? 

Ans. That is a boiler-maker's job, and it is some- 
times done by re-riveting the gussett stays which 
hold the ends and sides of the boiler together. 

Ques. Name other things causing overstraining ? 

Ans. Overheating the plates, resulting from the 
use of impure water — this is a very frequent cause 
of the failure of comparatively new boilers, the 
deposits cause uneven expansion and contraction. 
Again, the presence of oils in the boiler, admitted 
with the feed water when taken from the hot well of 
a jet condensing engine, or admitted with the steam 
from the cylinders. This, especially where the water 
contains carbonate of lime, is responsible for a great 
deal of the trouble arising from straining. 



QUESTIONS AND ANSWERS. 35 

Questions and Answers Relating to Incrusta- 
tion and Scale. 

When steam is used through the cylinder or heat- 
ing pipes, all of the impurities, existing in nearly 
all water, remain to vex the engineer, to impede the 
action of the generator, and to ultimately even des- 
troy it. For instance, a 150 h, p. boiler will evapor- 
ate at least 30,000 lbs. of water in each day of ten 
hours, and in a month, say, 400 tons. In a compara- 
tively pure water there would be 100 lbs. of solid 
matter in that quantity, and in many kinds of spring 
water as much as 2,000 lbs., and all this remains 
after the steam is removed. In some " river waters" 
such has been the condition of the interior of the 
steamboat boilers that it has resembled " mush " in 
consistency. 

The impurities are simply foreign bodies, which 
have no legitimate place in the boiler, and are to 
be expelled as dangerous foes. 

The sediment remaining after the extraction of 
the steam forms scale ; and the presence of scale or 
sediment in a boiler results in loss of fuel, burning 
and cracking of the boiler, predisposes to explosion, 
and leads to extensive repairs. It is estimated that 
the presence of 1-16 inch of scale causes a loss of 13 
per cent, of fuel, }£ inch 38 per cent., and ^ inch 60 
per cent. 



ENGIXEERS' EXAMINATIONS. 



Ques. what effect does the accumulation of scale on the 
interior, and of soot on the exterior of a boiler, have upon 
the economy of the boiler ? 

Ans. The result is to largely increase the amount 
of fuel consumed, frequently as much as one-fourth 
in cases of bad scaling. 

The most common defects produced are serious 
leakage around tube ends, incrustation and scale, 
deposit of sediment, external corrosion, internal 
corrosion, and defective pressure gauges. 

(Jues. Is scale all of one kind ? 

Ans. No. The nature and hardness of the scale 
depend upon the kind of substance held in solution 
and suspension by the water in the boiler. 

Ques. What general course is the best in dealing with the 
sediment ? 

Ans. It is more profitable to soften and filter the 
water than to trust to blowing out or dissolving the 
sediment and scale after it is there. 

Ques. What is the action of a scum-cock ? 

Ans. Nearly all foreign matter held in solution in 
water, on becoming separated by boiling, rises to 
the top in the form commonly called scum, and every 
boiler should be provided with means for blowing 
out water from the surface in order to remove the 
fine particles of foreign matter floating there ; as, if 



QUESTIONS AND ANSWERS. 37 

not removed the heavier particles will be attracted 
to each other until they become sufficiently dense to 
fall to the bottom, where they will be deposited in 
the form of scale. 

Ques. Can a mixture be made to use in a great majority 
of cases of scale. 

Ans. One that has been strongly recommended is 
made up of 40 lbs. of sal soda, to which is to be 
added 5 lbs. of catichu and 5 lbs. of salamoniac — 
one lb. of the mixture to be added to each barrel of 
water used, until the scale disappears, when the use 
of sal soda alone is all that is necessary. 

Qiies. Can one preparation be made that will be beneficial 
in all cases of deposited sediment ? 

Ans. No. This is owing to the variety of chemi- 
cal matter contained in water, and the varying 
quantities existing in the steam generators, to say 
nothing of the different temperatures in which the 
" compound " may be expected to operate. 

Ques. What is essential in the design of a boiler in ref- 
erence to the sediment ? 

Ans. It is absolutely essential to the successful 
use of any boiler, except in pure water, that it be 
accessible for the removal of scale, for, though a 
rapid circulation of water will delay the deposit, 
and certain chemicals introduced into the water may 
lessen it, yet the only certain cure is periodical in- 
spection and mechanical cleaning. 



38 ENGINEERS' EXAMINATIONS. 



Questions and Answers relating to the Steam 
Boiler. 

Ques. AVliat are the principal forms of steam generators ? 

Ans. There are three, stationary, locomotive and 
marine, which terms explain for what uses they are 
built. 

Ques. Name some of the boilers which come under the 

heading of stationary. 

Ans. The Horizontal Plain Cylinder ; the Two 
Flue ; the Horizontal Tubular ; the Water-tube ; 
the Cornish ; the Sectional, etc. 

Ques. Which form is the one most largely in use ? 
Ans. The Horizontal Tubular. 

Ques. What are its special advantages 1 

Ans. This type is the result of many years of 
experiments, and aside from a liability to an occa- 
sional explosion, has proved itself best adapted to 

the wants of steam users. 

Ques. Name some of its special " points " of advantage, 

Ans. It is the cheapest in construction ; it is 
cylindrical; it encloses the greatest volume of water 
and steam with the least material ; it is very access- 
ible for cleaning out and it resists internal and 
external strains with equal excellence. 



QUESTIONS AND ANSWERS. 39 

Ques. What is the pecixliar difference between water tube 
boilers and others ? 

Ans. The fact of the small tubes being used for 
holding the water — the distinction is expressed by 
denominating the older type 'fire tube " boilers. 

(^ues. Name the advantages claimed for water tube boil- 
ers. 

Ans. The principal claim for superiority is that 
they are supposed to be safe from disastrous explo- 
sions. This is owing to the small size or diameter 
of the tubes of which they are built. 2d. — They are 
quick "steamers." 3d. — Are accessible for repairs 
and cleaning and are easily transported — being con- 
structed in small sections — and easily set up. 

Ques. What are the known disadvantages of the water 
tube system ? 

Ans. While they make steam quickly, the press- 
ure as quickly subsides, owing to the small reserve 
in the water space; the use of cast-iron used in their 
construction has frequently worked badly in prac- 
tice and they are said to be more liable to " prime " 
Ihan other forms. 

Ques. Has any particular form of steam boiler proved 

itself absolutely the best ? 

Ans. No. Tests prove that a square foot of 
heating surface in both systems, if properly set and 
with an equally good draft, evaporates nearly the 



40 EWGIN'EERS'' EXAMINATIONS. 

same number of pounds of water to a pound of 
coal. 

Ques. What is the essential peculiarity of the marine 
boiler ? 

Ans. By U. S. Law all marine boilers must be 
constructed so that they are fired internally. They 
are not allowed to be " set " in brick work. 

Qnes. What is Irhe essential peculiarity of the locomotive 
boiler ? 

Ans. In that it has the steam engine attached to 
it, thus making it, as it were, a combined engine 
and boiler, which, with the steam-blast invented by 
Geo. Stevenson, forms as near a live thing as is 
known in the world, of man's creation. 

Qiies. About how many pounds of water can be evapora- 
ted per pound of coal by an ordinary boiler ? 

Ans. From seven to eleven pounds, depending 
upon the quality of the coal, the draught, and the 
thickness of incrustation on the interior of the boiler 
and amount of soot and ashes on the shell and in 
the tubes. 

Ques. What part of the steam boiler is the strongest '? 

Ans. The strength of a boiler is only that of its 
weakest part; hence boiler makers are always study- 
ing methods of perfecting the structure so that every 
portion has the same resistance. 

(J lies. What is the great cause of steam boiler explosions ; 



QVESTTONS AND ANSWERS. 41 

Ans. Weakness in the boiler to withstand the 
pressure. When a boiler is strong enough to hold 
the steam it will not explode. 

(^ues. What produces this weakness ? 

Ans. Generally by overheating the plates, caused 
by shortness of water. When the sheets are heated 
to a certain point they lose their power of cohesion 
and become very weak. This causes them to bulge 
or come down ; and where the pressure is suddenly 
increased by pumping in water, an explosion takes 
place. 

(Jues. What other causes can you name which are liable 
to produce an explosion ? 

Ans. Excessive pressure, beyond the limit for 
which the boiler was designed ; by bad workman- 
ship in punching and riveting the sheets ; by bad 
material used in the construction of the boiler ; by 
the collection of mud and scale ; and by bad design 
in which the boiler may not be properly strengthened 
by stays and braces. 

Qiies. Have you any particular "theory -' as to boiler ex- 
plosions t* 



*A press despatch from Haverhill, Mass., tells of a hundred horse power 
boiler which recently sailed into the air like a sky rocket, paused for an 
instant, then exploded with a deafening report and a concussion which 
shook the city like an earthquake, and great pieces of iron fleiv in all 
directions. The cause of this phenomenon is said to have been that the 
fireman of a hoisting engine boiler fired up at a time when the boiler con- 
tained an insuflScient amount of water. 



42 ENGINEERS' EXAMINATIONS. 

Ans. No. I simply consider an explosion the 
natural consequence of " letting go " of the forces 
locked up in the steam and hot water, when sud- 
denly released from the power of resistance in the 
generator — being like the "popping" of corn, where 
the moisture of the kernel is turned into confined 
steam by heat, until the pressure becomes too great, 
when an explosion takes place which shatters the 
grain. 



QUESTIONS AND ANSWERS. 43 



Questions and Answers Relating to Firing. 

Ques. How thick should be the body of coal in the fur- 
nace ? 

Ans. The thickness of fire to be carried depends 
altogether on the draught. If the draught is strong 
it should be heavier than when it is weak, and a 
bituminous (soft) coal fire should be thicker than 
one of anthracite (hard) coal. For hard coal three 
to six inches should be the depth, and for soft coal 
five to eight inches. 

Ques. How should the coal be spread ? 

Ans. It should be kept spread evenly all over the 
grate, and not allowed to burn in holes, leaving the 
bars bare, as the cold air will rush in and chill the 
heating surface. 

Qiies. What is the proper way to clean a fire ? 

Ans. Take a hoe and push the upper part of the 
fire back, leaving the clinkers, ashes, etc., on the 
grate ; then pull the ashes, etc., out with the hoe. 
To clean the back end of the grate, you pull the 
good fire forward again, and draw the clinkers and 
ashes of the back end over the fire, and into the ash- 
pan. Having cleaned it, you must spread the fire 
evenly all over the grate, and then cover it over with 
fresh coal, but not too heavily. Care must be taken 
with anthracite coal, not to let the fire burn too low 



44 ENGINEERS' EXAMINATIONS. 

before cleaning it, or else you will not have fire 
enough left to cover the grate, and it will die out. 

Ques. Can you add anything else about firing ? 

Ans. Whatever is done to a fire should be done 
quickly, and the furnace door be kept open no longer 
than necessary. No two fires should be cleaned at 
the same time. A soft coal fire needs breaking up 
at short intervals, as it has a tendency to amalga- 
mate, or crust over on top ; but a hard coal should 
not be broken up with the bar. All that is necessary 
to clean it of ashes is to run the slice bar over the 
grate, and withdraw it without breaking up the fire. 

Qiies. In case of a fire threatening the destruction of the 
whole establishment, what is the first thing to be done ? 

Ans. The fire under the boilers should be drawn, 
and the safety valves propped open, so that no explo- 
sion may take place after the place has been left, this 
being done for the safety of the engineers, firemen 
and others. 

Ques. How would you fire a locomotive ? 

Ans. I would distribute the coal — after the fire 
is well started — evenly in a strip about a foot wide, 
along the side-sheets and in the corners, being care- 
ful that there are no holes along the side-sheets and 
in the corners. This leaves a strip across the fire- 
box, from the fire-door to the flue-sheet, that J do 
not put any coal on. 

Ques. How does the coal get into the center ? 



QUESTIONS AND ANSWERS. 45 

Ans. I claim that the engine does it. When the 
coal is put into the fire-box the heat soon drives the 
gas and other matter out, converting it into coke, 
and coke being very light the draft will carry it to 
center of filre-box. The corners and along the sides 
being a little higher after coal has been put in also 
aids the draft. The fuel furnished to this strip 
being coke, it takes very little air to burn it, and the 
draft drawing the gas from the sides to center of 
box gives more chance for air and gas to come in 
contact and burn. 

Ques. Has this method been tried or is it a theory ? 

Ans. It has been tried and it is claimed that a 
saving of lo per cent, can be made. 

(^iies. Wliat should be the first aim in firing ? 

Ans. To keep an even pressure on the boiler ; 
to adjust the firing to the work demanded of the 
engine. 

Ques. What other general rule would you recommend ? 

Ans. To handle the fires, the water supply and 
the management of the steam without sudden 
changes — allowing always a sufficient time for the 
different forces to adjust themselves to their changed 
conditions. 



ENGINEERS' EXAMINATIONS. 



Questions and Answers Relating to the Cir- 
culation of Water in a Boiler. 



>X-V/ 




Ques. What is circulation of water in a 
boiler ? 

Ans. When a body of water is 
heated through the shell of a boiler a 
movement takes place, and the heated 
particles rise to the top, and the 
cooler particles from above take their 
place. These particles of water do 
not move the same in all parts of 
the boiler, in some portions the 
movement will be upward and in 
other portions downward, and in this 
way the circulation in a boiler is pro- 
duced. 

(^ues. What particular force, or energy, 
produces this movement ? 

Ans. Heat. The movement of 
the water is due to the difference in 
weight of the particles. The water at 
the bottom becomes heated and 
expands in consequence, and thus 
becoming somewhat lighter than the 
colder particles, is forced upward by 
the greater density of the cold water 
above. In this way, too, heat is 
diffused throughout the whole body 
of water in the boiler. 



Note.— The cut shows the ebullition as it goes 
on in a restricted space. 



QUESTIONS J-ND ANSWERS. 47 

Qnes. Is there any other force which comes into action 
to produce tlie circulation ? 

Ans. Yes. The columns of rising steam obtain 
great physical power, violently and mechanically 
forcing upwards the water which comes in their 

way. 

(}aes. Is it important to provide for these rising globules 
or columns of steam ? 

Ans. The flues and water spaces in boilers should 
be so arranged as to provide a regular and unre- 
stricted circulation of both the downward and the 
upward flow of hot water and the upward rush of 
the steam. 

Qiies. Where does the movement of the particles begin ? 
Ans. At the bottom. 

(^ues. In what department is the knowledge of the circu- 
lation of heated water most needed ? 

Ans. In the steam and hot water heating of 
buildings and work shops, etc. 



48 ENGINEERS' EXAMINATIONS. 



Questions and Answers Relating to Combus- 
tion of Coal. 

Ques. What does the word combustion mean ? 
Ans. To burn, to kindle, to light. 

(^ues. Before any bm-ning of coal can take place what 
must occur ? 

Ans. The coal must suffer the preparatory pro- 
cess of decomposition. It must be dissolved in 
minute particles of gas or coke. In the combustion 
of bituminous, or soft coal, there are two distinct 
operations, viz.: the distilling of the gas and its 
combustion, and the combustion of the remaining 
solid carbon or coke. 

Ques. What part is first consumed ': 

Ans. The gas. This unites with the oxygen of 
the air and burns first. 

Ques. What burns next ? 

Ans. The coke, in the same way as the gas, /. e., 
the particles of the coke unite with the oxygen of 
the air and it in turn is consumed. 

(^ues. How is the gas ignited ? 

Ans. The heat under which the gas itself distills 
will always ignite it if the due admixture of air is 
immediately obtained. 



QUESTIONS AND ANSWERS. 49 

Quos. Is it necessary to have air admitted, and if so, 
xvbich is the best manner of supplying it to the fuel in order 
that it may be most effectively consumed ? 

Ans. Air is absolutely essential and is best 
admitted through the grate-bars to the furnace in 
innumerable fine jets, since gas and air mix only 
gradually. Air in bulk mixes only superficially with 
gas, and, by abstracting heat, cools the furnace. 
Gases to be thoroughly burned in the furnace must 
be intercepted at the start, else the combination, 
which is at best gradual, will not be completed in 
season. 

(^ues. As to air entering the furnace above the burning 
fuel, is it desirable ? 

Ans. A proper amount of air (oxygen) entering 
the furnace above the fuel in small quantities assists 
somewhat in the combustion of the gases, but a 
great quantity is detrimental and injurious. 

<{ues. Is there any other theory about this ? 

Ans. Ves. It is claimed that if the fuel is not 
put on the grate in too thick a layer no necessity for 
such introduction of air is necessary. 

Ques. In supplying air to the furnace is it an ad .'antage 
to have it heated ? 

Ans. Probably not. There are certain practical 
objections to heating the air supply for boiler fur- 
naces. First, for every 480 degrees Fahr. of added 
heat its bulk is enlarged by the amount of its 



50 



ENOINEEBS' EXAMINATIONS. 



original volume, so that at 3000 degrees, the heat of 
the interior of the furnace, it has six times its 
original volume. It is, consequently, more unman- 
ageable ; and as its contained oxygen retains the 
same weight, its mixture with the gas becomes moie 
difficult, while when mixed it can only do the same 
work as before. It would be much better to con- 
dense the air than to expand it. Next, if heated by 
passing through flame or over burning coal, the air 
will be robbed of a greater or less part of its vital 
oxygen. This is a positive loss. 



Table of Heat of Combustion. 



Combastible. 



Total units of 
heat of com- 
bustion per lb. 



Lbs. of water 

evaporated 

from and at 

212°. 



Hydrogen 

Carbon burned to carbonic 

oxide 

Carbon burned to carbonic 

acid 

Anthracite 

Bituminous coal .... 

Coke 

Cannel coal . 

Petroleum 

Coal gas 

Oak wood (dried) ... 



62,033 

4,400 

14,500 
14,700 
14,000 
13,640 
14,000 
20,360 
20,800 
7,700 



64-2 

4-55 

15-0 
15-2 
14-5 
141 
14-5 
31 
21-5 



QUESTIONS AND ANSWERS. 53 



Ones. What is the combustion chamber ? 

Ans. It is that space under the boiler wnere the 
burning or combustion of the fuel takes place. 

(Jues. What is the first essential in the construction of the 
combustion chamber ? 

Ans. It must be large enough, as the fuel before 
burning must be enormously expanded. It is said 
that a lump of coal the size of a man's fist or less, 
must be expanded so that it occupies a cube meas- 
uring nine feet each way— hence the combustion 
chamber must be very large indeed compared with 
the space occupied by the solid fuel as it is placed 
upon the grate bars. 

Ones. Give the successive processes of combustion as 
developed in making a coal fire. 

Ans. It is a pi-ogressive process, i, The match, 
by friction, ignites the phosphorus on its tip, at 150° 
Fahrenheit ; 2, this sets fire to the sulphur at 500" ; 
3, this causes the soft wood of the match to burn at 
800° ; 4, which in turn fires the coal at 1,000°; 
5, at this point the coal unites with the free oxygen 
of the air and carries the furnace heat up to 4,000°, 
more or less, and completes the process. 

Ques. What is a combustible ? 

Ans. Something which burns— coal, oil, wood, 
are combustibles. 



5a ENGINEERS' EXAMINATIONS. 



Questions and Answers Relating to the Cofi 
struction and Strength of Steam Boilers, 

Ques. Of what material are boilers built ? 

Ans. Of sheet steel, as owing to furnace im 
provements this superior metal can now be madt 
cheaper than wrought iron, and, moreover, mild steel 
has proved to be the best. 

Ques. What is the process of joining the sheets together 
called ? 

Ans. Riveting, although in certain cases the 
sheets have been welded, avd in time this may 
become the general rule. 

Ques. What are the two principal kinds of riveting ? 

Ans. Two — single and double. Single riveting 
for the girth seams of the boiler and double for the 
lengthwise seams. In the latter the rivets form a 
zig-zag line at each joint or seam. 



NOTE.-THE AMERICAN BOILER MAKERS standard of 
strength, for steel boiler plate is as follows : " Tensile 55,000 to 65,000 
lbs. per SQuare inch of section ; elongation in 8 inches 20 per cent, for 
plates % inch thick and under ; 22 per cent, for plates % inch, to ^ 
inch ; 25 per cent, for plates % inch and under. Specimen piece must 
bend back on itself (cold) without fracture ; for plates over J4 inch 
thick specimen must withstand bending 180° (J^ way) round a mandril 
13^ times the thickness of the plate. Chemical requirements ; phos- 
phorus not over .04C per cent.; sulpbar ■aot over .030 per cent." 



QUESTIONS AND ANSWERS. 



Ques. What size rivets are used in joining the sheets ? 

Ans. They are long enough to bend over and 
form a head, and of a diameter suited to the different 
thickness of the plates, ^, ^, ^, according to the 
specifications for making a boiler when it is first 
constructed. 

Ques. What is the thinnest sheet which should be used in 
a boiler ? 

Ans. One-quarter of an inch ; this is the thinnest 
which can be caulked to advantage. 

Qnes. What is caulking ? 

Ans. This is the closing of the seams after the 
riveting has been done, and is executed by a blunt 
chisel ; when the work is done by a round nosed 
chisel it is called "fullering." 

C^ues. Is a thin plate better than a thick one ? 

Ans. It is said by practical boiler makers that 
the thinner the sheet — so long as it affords sufficient 
strength — the longer it will last under the varying 
strains to which a steam boiler is subjected, and that 
the caulking will also last longer and better. 

Ques. What are the flanges of a boiler ? 

Ans. They are those parts which are bent over ; 
this is called flanging ; for example, the heads of the 
tubular boiler are turned over to be joined to the 
shell, or body sheets. 



54 ENGlNBEttS' EXAMWATIONS. 

Ques. What are the "lugs " of a boiler ? 

Ans. The lugs are the castings riveted on each 
side of the boiler which support or "lug" it. There 
are commonly three or four lugs on each side. 

(|ues. Suppose the water should fall below the lowest 
gauge-cock, what is to be done ? 

Ans. If the fires are light, they should at once be 
hauled; but should they be heavy, the better plan is 
to smother the fire with fresh coal, dust, or ashes 
out of the ash-pans. 

Ques. What are the two principal methods of testing 
steam boilers ? 

Ans. There are two methods in general use, 

known as the " hydrostatic test " and "hammer test." 
The former test consists in filling the boiler with 
water, and then with a hand force-pump raising the 
pressure up to that which it is supposed the boiler 
will stand. The "hammer test" is applied in ah 
accessible parts of the boiler, such as the shell 
fiues, and braces, by tapping with a light hammer. 

Qiies. What is meant by the pitch line of riveted work ? 

Ans. The distance from center to center of the 
rivet. 

Ques. How far from the edge of a sheet may a rivet hole 
be properly made ? 

Ans. A distance equal to the diameter of the 
rivet hole, /. e., the space between the edge of thf 



QUESTIONS AND ANSWERS. 55 

rivet hole and the edge of the sheet must equal the 
diameter of the rivet. 

(Jues. Does the removal, or punching out, of the metal 
for the rivet hole weaken the plates and consequently the 
boiler ? 

Ans. Yes. 

(^ues. What is the rule as to pitch of the rivets in view of 
this weakening ? 

Ans. There shall be the same strength of iron 
between the rivets as there is in the rivets themselves. 

(Jiies. What is the most advantageous thickness of boiler 
plates ? 

Ans. It has been found by experience that a 
thickness of about ^ of an inch is the most favor- 
able to sound riveting and caulking of boiler plates; 
and they are seldom made much thicker or thinner 
than that thickness; if more strength is needed in a 
boiler it is better to reduce the diameter of the shell 
than to increase the thickness of the plates. 

Ques. Is h usual to inake the heads thicker than the shell i 

Ans. Yes. Where the shell is ^ the ends aiv 
made ^ inch, and in that proportion. 

(Jues. What is the name of the round plate vrhich forms 
the ends of a tubular boiler ? 

Ans. The tube plate, because in it the ends of 
the tubes are riveted and bearied. 



56 ENGINEERS' EXAMINATIONS. 

(^ues. How many principal kinds of seams are there in 
boilers ? 

Ans. The " lap " and the " butt " joint, the names 
of which signify the way in which the sheets are 
riveted. 

(^ues. How do you ascertain the strength of a riveted 
seam? 

Ans. It is customary to multiply the tensile 
strength of the metal by .70 or rs for double 
riveted longitudinal seams and .56 for single riveted- 

Ques. Give an example. 

Ans. If the steel plates have 60,000 lbs. tensile 
strength per square inch, then ^ of the square 
inch would be 22,500 lbs. — multiplying this by. 70 
gives 15,750 pounds as the strength of the double 
riveted seam. 

Or multiplying by .56 it gives 12,600 as the 
strength of the single riveted seam. 

Ques. How does the strength of a seam compare to that 
of a solid sheet ? 

Ans. The custom is roughly to consider the 
strength of the single riveted seam to be one-half 
that of the solid sheet and the double riveted three- 
fourths. 

^ues. When inspectors figure the allowable pressure upon 
a boiler how do they proceed ? 



QXmSTlONS jilVD ANSWERS. 0^ 

Ans. They take the strength of the seam and the 
strength of the weakest plate. They also figure the 
size and pitch of the rivet. 

Ques. Can jou give a short rule for determining the 
strength of a boiler — taking the weakest sheet ? 

Ans. Multiply the thickness of the weakest plate 
in the boiler by its tensile strength per square inch 
in pounds, and divide the product by one-half of the 
diameter of the boiler in inches, and multiply the 
product by .56 for single riveted longitudinal seam^ 
and by .70 for double riveted longitudinal seams. 

Ques. What will be the strength of a boiler with }^ inch 
plates of 50,000 lbs. tensile strength, double riveted, and 
boiler 40 inches in diameter ? 

Ans. One quarter plate gives }( of the strength 
of the square inch of section = 12,500; divide this 
by j/2 (of 40 in, diam.) 20 = 625 lbs. This would be 
for a solid sheet; for double riveted multiply by 
is = 437tSs lbs. total strength. 

Ques. Would inspectors allow this as the pressure to be 
carried? 

Ans. No, for they have, by law and custom, " a 
factor of safety," which only allows one-fourth to 
one-sixth. 

Ques. With a factor of six, how much willl be allowed m 
this case? 

Ans. About 75 Jbs 



68 t]]S/aiNEt:WS EXAMINATION^. 

Ques. With a factor of five, how much ? 

Ans. About 85 lbs. — the figure being approxi- 
mated by the inspector — if needed. 

(^ues. "What have you to say as to grate bars ? 

Ans. When the furnace is more than four (4) feel 
long the bars should be put in in two lengths, but if 
it is four feet or less in length, one bar will suffice, 
in which case only two bearing bars will be required. 
When a center bearing bar is used for two lengths, 
it should be made like a double grate-bar — that is, 
with an opening or air-space in the middle. Grate- 
bars when hot expand considerably, and therefore 
they should not be put in tight, or too close together, 
but should have end and side play, otherwise they 
will bend and twist out of shape and soon be 
destroyed. 

Ques. Does heating a boiler in the regular "firing" 
weaken or strengthen it ? 

Ans. It strengthens it, because wrought iron 
heated to a point less than 600° Fahr. increases in 
strength, and as at 200 lbs. pressure on the boiler per 
square inch the temperature is less than 400°, it fol- 
lows that it grows stronger.* 



*NoTE. — Under a test it has been shown that the strength of irou 
increases up to 570°, when it begins to decrease with the added heat. 
At 32° it was 56,000 lbs. per square inch. 



570° " 


" 06,500 " 


r3o° " 


" 55,000 " 


i050° " 


" 33,000 " 


?.240° " 


" 23,000 " 


1317° " 


" 9.000 " 



QUESTIONS JiND ANSWERS. 



Questions and Answers Relating to the 
Physical Properties of Steam. 

Ques. What is steam ? 

Ans. Steam is an invisible elastic fluid, or water, 
brought to the state of gas by the application of 
heat. 

(^ues. What is live steam ? 

Ans. Live steam is steam under pressure and ready 
to do work through the agency of the steam cylinder 
or for heating, boiling, etc. 

Ques. What is dead steam ? 

Ans. Dead steam is the opposite of live steam 
— such as exhaust steam or the vapor which fills the 
steam generator before there is any pressure. 

Qiies. What is dry steam ? 

Ans. Dry steam is that which holds no water in 
suspension. High pressure steam has been proved 
by experiment to be dry like dust. 

i^ues. Wliy is steam invisible except as it is oeing con- 
densed ? 

Ans. Like many other gases it possesses the 
quality of invisibility. 

(^iies. What is saturated steam ? 

Ans. This is steam under pressure in contact 
with water in the boiler; its condensing point agrees 
with the boilins" point of the water on which it rests 



60 ENGINEERS' EXAMINATIONS. 

(^ues. What are the constituents of which steam i» 
formed ? 

Ans. It contains the same elements as the water* 
of which it is formed, /. e., two gases, oxygen and 
hydrogen. 

(^ues. In what proportions do these exist in water and 

steam ? 

Ans. Two volumes of oxygen and one volume 
of hydrogen, but in weight the hydrogen is the 
lightest. 



(Jues. Are the oxygen and hydrogen (gases) found in coal 
the same substances as those described in above answer ? 

Ans. Yes, because these two are simple bodies in 
themselves, while found in thousands of combina- 
tions with other original elements. 

Ques. If water is confined in a boiler, and the vessel en- 
tirely full, and then heated to a high temperature, will there 
be any steam formed. - 

Ans. No, because steam requires space in which 
to expand. 

Qnps. How many times is water expanded in being 
ciiauged into steam at tlie pressure of the atmosphere ? 

Ans. Into sixteen hundred and sixty-nine time,, 
the volume ; or roughly, 1,700 times. 

Ques. What occurs in the expansion when a pressure is 
placed upon the boiler ? 



QUESTIONS AND ANSWJERS. 61 

Ans, It expands according to the pressure. The 
greater ihe pressure the less the volume. This is 
given in tables carefully computed; at a pressure of 
150 lbs. TO the square-inch the volume is reduced 
to 284 times, and at 300 lbs. pressure to 96 times. 

(^ues. What is superheated steam ? 

Ans. When steam is separated from the water 
over which it was formed, and afterwards re-heated 
to a higher temperature than the water and steam 
it becomes superheated steam. 

(J lies. Which is the heaviest, a pound of steam or a pound 
of water ? 

Ans. A pound of steam is the same in weight as a 
pound of water. It is good form to say that the 
engine uses " so many pounds of steam " instead of 
so many pounds of water. 

Qiios. Which is the heavierit at atmospheric pressure, 
steam or air ? 

Ans. Steam is the lightest, because it always 
rises. It is about two-thirds the weight of air. In 
the tables it is put down at .625. 

Qucs. When air is confined with steam inside the boiler, 
which is then the heaviest ? 

Ans, Both being under more than atmospheric 
pressure (14 lbs. to the inch), air will be the lightest 
because its rate or ratio of compression is greater. 
/. e., steam compresses more readily than air. 



63 ENGINEERS' EXAMINATIONS. 

Ques. Is air confined in the boiler with steam considered 
hurtful or dangerous ? 

Ans. No, as with the immense vohime of steam 
being formed and used through the engine it soon 
passes off. Some engines are altogether operated 
by compressed air. 

Ques. What is wet steam ? 

Ans. Steam full of spray — or with water mechan- 
ically suspended in the steam. 

Ques. What is the difference l)etween high and low pres- 
sure steam '? 

Ans. High pressure steam is commonly under- 
stood to mean steam used in high pressure engines, 
and low pressure steam is that used at low pressure 
in condensing engines, heating apparatus, etc., at 15 
lbs, pressure or under. 

Ques. At what temperature does water evaporate ? 
Ans. Water evaporates at all temperatures above 
freezing point, and boils at 212°. 

Qucs. What is absolute pressure of steam ? 

Ans. Absolute pressure is its pressure estimated 
or reckoned above vacuum ; or the steam pressure 
shown by the ordinary steam gauge with the pres- 
sure ot the atmosphere added ? 

Ques . V/hat is initial pressure ? 

Ans. Initial pressure is that in the cylinder of 
an engine at the beginning of the forward stroke of 
the piston. 



QUESTIONS AND ANSWERS. 63 

Ques. What is terminal pressure ? 

Ans. Terminal pressure is that which would be 
in the cylinder at the end of the stroke of the piston 
if the exhaust valve did not open until the stroke 
was finished ? 

(Jues. What is wire drawing ? 

Ans. Wire drawing is the operation of reducing 
the pressure of steam between the boiler and 
the cylinder ? 

Ques. Does the change from water to steam, by the ap- 
plication of heat, affect the relation of the particles of the 
different fluids ? 

Ans. As water, the particles are strongly co- 
hesive, but as steam the particles are repellent. It 
is this repellant force existing among the infinitely 
small atoms of steam which appears to give the 
energy to the mass of steam and renders it service- 
able. 

Qiies. Does this change mean anything looked at as 
power ? 

Ans. The fluid, as water, is inexpansive, but the 
change to steam gives it energy or the ability to do 
work by the reason of its great expansive or elastic 
tendency. 

Ques. Has the process we call boiling anything to 

do with steam ? 

Ans. Yes. Boiling is caused by the formation of 
s^team particles. 



64 THE STEAM ENGINE. 



THE STEAM ENGINE. 



While machines may vary greatly in different particulars, 
the laws of matter are the same, and will remain unchanged 
for all time ; hence it must be borne in mind that success in 
the design, care and management of an engine, no matter 
what may be its size, kind or use, can only be achieved by 
a close observance of the fundamental laws which govern 
the formation and use of steam. 

All steam engines may be divided into two great classes, 
according as they are or are not provided with apparatus for 
condensing the steam. These classes are: 1, condensing, or 
low pressure engines; 3, non-condensing, or high pressure 
engines. 

Engines of the second class are on the whole less econom- 
ical of fviel than those of the first class, but, having fewer 
parts and occupying less space, they are much used where 
simplicity and compactness are considered of more impor- 
tance than economy of fuel. 

A second mode of classing steam engines is founded on the 
way in which steam acts on the piston, and is as follows : 

1. Single acting engines, in which the steam performs it& 
work by its action on one side of the piston only. 



THE STEAM ENGINE. 65 

2. Double acting engines, in which the steam exerts 
energy on eitlier side of the piston alternately. 

3. Rotatory engines, in which the steam drives a revolving 
piston round. 

A third mode of classification distinguishes engines into — ■ 

1. Non-rotative, in which no continuous rotation is pro- 
duced, as in single acting pumping engines, steam hainmers, 
etc. 

2. Rotative engines, in which the motion is finally com-- 
municated to a continuously rotating shaft. 

Rotative engines are now the most common. Non-rotative 
engines are exceptional. 

A fourth mode of classing engines is founded on their 
purposes, as follows : 

1. Stationary engines, such as those used for pumping 
water, for driving manufactory machinery, etc. 

2. Portable engines, which can be moved from place to 
place but are stationary when at work. 

3. Marine engines, for propelling vessels. 

4. Locomotive engines, for propelling vehicles on land. 

Stationary engines exist of all the classes belonging to the 
three previous modes of classification. Portable engines are 
usually non-condensing, to save space, and to adapt them to 
situations where injection ^vater cannot be obtained in suffi- 
cient quantity. Most of them are also double acting and 
rotative. Marine engines are in general condensing, double 
acting and rotative. Locomotive engines are aknost all non- 
condensing, and are all double acting and rotative. 



THE STEAM ENGINE. 



In the selection of an engine there are six points to ob- 
serve relating to it before its purchase : 

L Its simplicity. 

II. Its strength. 

ni. Durability and least wear. 

IV. Economy in the use of steam, 
V. Regularity of speed. 

VI. Fitness for its work. 

Any intelligent engineer has observed that his engine has 
an individuality not possessed by any other, and a personal 
acquaintance with its peculiarity is quite necessary to obtain 
the best results from it. This remark applies with equal or 
greater force to the steam boiler and steam pump, and the 
successful engineer or fireman is the one quickest to under 
stand "the points " of his machine. 

Great progress has been made in the art of engine building 
since the introduction of electric hght and power plants and 
every indication is that still greater perfection will be gained.* 

*NoTE.— In marine engineering the progress in coal economy has 
been wonderful as may be seen from the following table :— 

Pressure of steam Consumption of 

S'ear, by boiler gauge coal per I. H. P 

persq. In. per hour. 

1330 2 to 3 lbs. 9.0 lbs. 

1840 8 " 5.5 " 

1850 14 " 4.0 ♦* 

I860 80 " 3.0 " 

1870 40 to 40 " 2.6 " 

1880 70 to 80 " 2.2 " 

1886 150 to 160 " 1.5 «* 

1889 175 " 1.4 « 

1890 300 *♦ 1.4 " 



QUESTIONS AND ANSWERS. 67 

Questions and Answers Relating to the 
Steam Engine. 



Ques. Along what lines has the latest development of 
steam engines been carried? 

Ans. There is a steady progress in the produc- 
tion of stronger, more rigid engines, using higher 
steam pressure and to run at higher speeds than 
now. The automatic cut-off is rapidly displacing 
the old throttling engine, and much attention is 
paid to condensers and the compounding of steam. 

Ques. What cause has operated to produce the necessity 
for stronger and more rigid engines and larger bearing sur- 
face? 

Ans. The higher speeds — loo revolutions per 
minute being now not uncommon. A speed of i6o 
revolutions per minute or 1120 ft. piston speed has 
been recorded in a 20x42 in. Corliss engine. 

Qnes. Which engine holds first rank as the most econom- 
ical and generally satisfactory type? 

Ans. The Corliss. 

Ques. In what cases has the compounding in the Corliss 
engine been found advantageous? 

Ans. Where large power is demanded. In 
smaller powers the ordinary simple expansion engine 
has been found sufficiently advantageous. 



68 ENGINEERS^ EXAMINATIONS. 

(^ues. What are the two great classes into which engines 
are divided? 

Ans. Throttling and automatic. 

Ques. Where is the difference? 

Ans. In the principle of regulation in supplying 
the steam from the boiler to the engine by auto- 
matic or throttling valves. 

Ques. Which is the oldest system? 

Ans. The throttling principle was almost uni- 
versal until Corliss introduced his automatic cut-off 
engine, which he made an immediate success by 
guaranteeing certain results from the use of a speci- 
fied amount of fuel. 

Ques. What is the advantage of the automatic cut-oflf as 
claimed by engine builders? 

Ans. It comes from the fact that most steam en- 
gines are subjected to variable loads, and quite 
generally some difference in steam pressure. The 
economical point of cut-off varies with the load, 
and the automatic cut-off governor so varies the 
amount of steam as to secure the best results, pres- 
sure being constant 

(Jues. In what j)laces are the throttling valve engines 
without objection ? 

Ans. Where there are but little variations, either 
in the pressure of steam or in the duty to be per- 
formed. 



QUESTIONS AND ANSWERS. 69 

Ques. What can be said about simplicity in an engine? 

Ans. It is always a point of great importance to 
build an engine containing the least number of parts 
and the simplest elements attainable in construction 
and design, such as the form of frame orbed, piston 
head, packing rings, cross-head, guides, connecting 
rod ends, valve gear, valves and regulating appli- 
ances. 

Ques. What about the strength of an engine? 

Ans. All parts should be so proportioned as to 
insure the greatest durability and to prevent tremors 
and strains. 

Ques. What about the point of durability? 

Ans. The least variation in the line of the en- 
gine, a slight settlement of the foundation, unequal 
wear of a bearing or failure of oil to flow but for a 
moment, will cause parts to heat, wear and ulti- 
mately fracture ; hence the new engine should be 
speeded only as fast as will enable the mechanism 
to continue its work with the least wear and stress, 
thus avoiding the error (now exposed) that the rate 
of speed of a perfectly constructed engine is unlim- 
ited. 

Ques. What can you say about economy in the use of 
steam? 

Ans. This is an element of vital importance and 
relates to the distribution of the steam in the 
cylinder. It embraces the least amount of clearance 
or dead space consistent with the smooth running 



70 ENGINEERS' EXA3IINATI0NS. 

of the engine, prevention of the loss of heat from the 
steam in the cylinder, an initial steam pressure in the 
cylinder equal to the boiler pressure ; a minimum 
back pressure ; rapid action of the admitting and 
cutting off edges of the valve ; a proper amount of 
cushioning ; and last but not least, a fitness of the 
engine for its work, in size and the character of the 
valve gear. 

Ques. Is I'egularity of speed m an engine of importance? 

Ans. One of the most essential features of a 
good engine is regularity of speed under varying 
loads. A high attainment in this respect is a vari- 
ation of only 3 per cent, in two revolutions. 

Ques. What have you to say about the fitness of an en- 
gine for its proper work ? 

Ans. It is of the utmost importance to choose 
an engine of the proper size and character to suit the 
work it is intended for. It is folly to purchase a 
fixed cut-off engine for greatly varying loads ; it is 
also poor economy to apply to a small steady load an 
expensive automatic cut-off engine, or one so large 
that the ratio of expansion becomes excessive and 
exceeds the limit of economy. Each steam plant 
requires its special engine lo be of the proper pro- 
portion. 

Ques. What is "clearance"? 

Ans. Clearance in a cylinder is the space allowed 
for the piston to clear the cylinder heads at the end 
or beginning of a stroke. 



QUESTIONS AND ANSWERS. 71 

Clearance is also a term used to include also the 
volume of the ports. It is evident that this space, 
as well as the space through which the piston sweeps, 
has to be filled with steam, 

Ques. What is "lead"? 

Ans. Lead is the amount of the opening of the 
steam port at the beginning of the stroke of the 
piston, sometimes called pre-admission. 

(Jnes. How would you give a valve its lead? 

Ans. Place the eccentric sheave ahead of its true 
position. 

(^ues. To cut the steam off at a given part of tlie stroke 
liow would ycm alter the valve? 

Ans. By making the width of the face of the 
valve larger or smaller, as the case demanded, 

(^iies. What would you call this then? 
Ans. Lap or cover. 

Ques. What is the "lap " of a valve? 

Ans. The "lap " is that part of a valve which is 
more than necessary to cover the steam ports when 
the valve is in mid-position. 

Qiies. Is there any lap on the exhaust valve? What is it? 

Ans, Theie is exhaust lap and it is how much 
the edge of the exhaust valve is over on the cylinder 
bar beyond the exhaust edge of the port when the 
valve is in mid-position, 



72 ENGINEERS'' EXAMINATIONS. 

i^ues. Why do we have lap on the exhaust edge? 

Ans. To get larger cushion. 

(^ues. What kinds of engines call for this? 

Ans. Those of great size and weight having 
short and very quick travel. 

Ques. Why is " lap " given a valve at all? 

Ans. To close the port before the piston reaches 
the end of the stroke, and thus make the steam work 
bv its expansion. 

Ques. What is the difference betvs^een fixed and movable 
expansion? 

Ans. The first is expansion by the lap of the 
valve, and the second is expansion by separate gear- 
ing or valves. 

i^iics. What other name is given the expansion valve for 

cut-off? ^ 

Ans. The " link." 

(^ues. Does the piston stop at any point of the stroke? 

Ans. Yes ; when passing the centre. 

Ques. What is the operation of the slide valve? 

Ans. To allow the steam to flow alternately first 
at one end and then to the other of the cylinder and 
open the opposite port alternately to the exhaust 

(Jues. What is the object of a crank? 

Ans. To convert a straight line motion into a 
circular one. 



QUESTIONS AND ANSWERS. 73 



Qucs. Describe the duties of a slide valve with reference 
to the positions of the piston? 

Ans, Steam is flowing into the cylinder and 
pushing the piston, then when the piston has trav- 
elled one-fourth or one-half or any part of the stroke 
before determined on, the valve must close the 
steam port to cause expansion ; it must again open 
this port to the exhaust just before the piston arrives 
at the end of the stroke so as to have a vacuum to 
commence the return stroke with ; it must close the 
exhaust a little before the piston arrives at the other 
end to cause cushioning and just before the end of 
the stroke, it must open this port to steam to com- 
mence the new stroke. 

Ques. What do we mean by a " vacuum " ? 
Ans. Any space void of all pressure. 

(^ues. Is an absolute "vacuum " obtainable"? 

Ans. No. 

Ques. Does the condenser have anything near a perfect 
vacuum? 

Ans. Yes, quite near ; but there is always a 
small pressure there. 

Ques. To show 11 lbs. what mvist the vacuum gauge read? 
Ans. 2 2 inches. 

Ques. What does 11 lbs. vacuum mean to a steam en- 
gineer? 



'J'4 ENGINEERS' EXAMINATIONS. 

Ans. It means that he can work his steam down 
to 4 lbs. before it exhausts, as the condenser has 
destroyed ii of the i5lbs. atmospheric pressure at 
which the steam would usually exhaust. 

(^ues. What is implied by the term "back pressure" ? 

Ans. As perfect vacuum is impossible, a certain 
vapor retards the piston equal to the distance be- 
tween a perfect vacuum and what the gauge reads. 

Ques. What is the difference between a high and low 
pressure engine? 

Ans. The first exhausts into the air, having no 
condenser, while the second exhausts into a con- 
denser, thus saving the pressure against the atmos- 
phere. 

(^ues. What is a compound engine? 

Ans. An engine built to get the same expansion 
not of the steam as does a simple engine, but by 
means of later cut-off. 

(Jiies. How do they contrive to do this? 

Ans. By using, in addition to the usiial high 
pressure cylinder, a large second cylinder, where the 
steam has additional room for expansion before es- 
caping into the condenser. 

Ques. Does water ever get into the cylinder, and what 
happens when it does? 

Ans. Sometimes water gets in through priming 
and is apt to split the piston or blow off the cover of 
the cylinder. 



QUESTIONS AND ANSWERS. 76 

(Jues. Can you get rid of this water? 
Ans. Yes, by the escape valves. 

(|ues. How can you reverse the motion of a slide valve 
engine? 

Ans. ist, place the engine on the dead centre, 
noting the amount of lead on the valve. 2d, slack 
up the set screw of the eccentric and turn it ahead 
(same way it has been running) on the shaft until 
the valve has moved to the extreme of its travel. 3d, 
move it back until it has the same lead as before, 
and tighten the set screw. 

Ques. In pvitting in a new shaft, how would you adjust 
the eccentric ? 

Ans. Put the crank on its top center with the 
valve at its proper lead at the top. Next fasten the 
sheave with set bolts to keep the valve lead secure ; 
when all is connected, then, after a turn of the 
engine, see if the valve has the proper lead at the 
bottom when the crank is on the bottom centre. If 
such is the case, mark the key ways, and key on the 
sheave. 

Ques. What is the cylinder? 

Ans. The cylinder consists of a cast iron true 
bored chamber and a steam chest or valve box. 

Ques. What are the openings from the steam cheat to the 
cylinder called? 

Ans. Steam ports. 



•re ENGINEERS' EXAMINATIONS. 

(Jues. Whicli are the exhaust ports? 

Ans. Those which open from the cylinder to the 



air. 



Ques. What is the "stuffing-box " ? 

Ans. The "stuffing box" is that part of the 
cover through which the piston passes. It is ren- 
dered steam-tight by a filling or packing of tallowed 
hemp, etc. 

(Jues. What is the ' ' gland " ? 

Ans. This is the cover which presses down the 
packing against the rod, and is secured by two 
screwed bolts. 

Ques. What is cylinder condensation? 

Ans. It is that portion of the steam which con- 
denses and is deposited on the metallic surface of 
the cylinder when the cylinder is colder than the 
steam entering it. 

(^ues. Does this moisture remain in the cylmder? 

Ans. No. It evaporates on the opening of the 
exhaust, thereby cooling the walls of the cvlinder 
again. 

(|ues. What is the result of all this? 

Ans. The steam is lost and a back pressure gen- 
erated thereby. 

(Jues. Is this loss verj^ great? 



QUESTIONS AND ANSWERS. 77 

Ans. Yes, sometimes being as much as 50^ of 
the whole steam consumed. 

Ques. How can this loss be partly remedied? 

Ans. I. By "jacketing " the cylinder with hot 
steam. 2. By " cushioning " or detaining and com- 
pressing (thus raising the temperature) a part of 
the exhaust steam, using the heat thus generated to 
keep the cylinder hot. 3. Compounding the 
cylinders. 

Ques. How would you test for a leaky slide valve ? 

Ans. Block the fly-wheel when the slide valve is 
in the middle of its stroke and open the indicator 
taps, or the relief cocks, or look at the exhaust pipe. 
A steady escape of steam indicates a leaky valve, 

Ques. How would you test for a leaky piston ? 

Ans. Block the fly-wheel when the piston is 
situated at a short distance beyond the beginning 
of the stroke. Admit steam to the piston and open 
the indicator tap^ or relief cock, on the exhaust side 
of the piston. An escape of steam will indicate a 
leaky piston. The leak may be caused by a leaky 
slide valve, so this should be tested fii^t. 

Ques. Should engines stand idle for any length of time, 
what should be done ? 

Ans. They should be turned partly round each 
day. 



78 ENGINEERS' EXAMINATIONS. 

^ues. What should be done before starting an engme ? 

Ans. The stop valve should be opened a little, 
before the fire is lighted, so that, while the steam is 
being generated in the boiler, it may pass through 
the cylinders and jackets and warm them gradually, 
the temperature rising as the pressure rises. Mean- 
while all drain cocks from the slide jackets and 
cylinders should be opened to allow the steam to 
flow through, and the condensed steam to pass 
away. This will prevent the possibility of the 
cylinder cracking owing to sudden admission of hot 
steam against the cold metallic walls of the cylinder. 
This is especially important in cold weather. 

Ques. How would you manage the drain cocks ? 

Ans. The drain cocks should remain open for a 
few revolutions till all water has been blown out of 
the cylinder, and then closed. 

(^ues. How about the oil ? 

Ans. I would see that all the lubricators were in 
pood condition, the holes clear, and the worsteds 
clean, and that the lubricators were well supplied 
with oil. 

Ques. If a low pressure or condensing engine, how would 
y©u proceed ? 

Ans. If a condensing engine, the vacuum gauge 
should be watched ; and, if the vacuum is not main- 
tained, the injection, or circulating water, should be 



QUESTIONS AND ANSWERS. 79 

regulated. If this does not produce the desired 
effect, there is probably an air leak through the 
piston-rod gland, or the air-pump-rod gland, which 
should be screwed up ; and, if the vacuum is still 
defective, the cause must be looked for in the foot 
and head valves or the air-pump bucket valve (if any), 
or in leaky condenser tubes. 

Ques. How is the horse power of steam engines deter- 
mined ? 

Ans. By the following rule : Multiply the area 
of the piston in square inches by the average forct 
of the steam in pounds and by the velocity of the 
piston in feet per minute ; divide the product by 
33,000, and TiT of the quotient equal the effective 
power. 

Ques. How is the "average force" of the steam in the 
cylinder, or, as it otherwise is expressed, the "mean effect- 
ive pressure ", fovmd ? 

Ans. The mean effective pressure can be accu- 
rately determined only by the aid of an indicator. 

Ques. Without the aid of an indicator how do you pro- 
ceed 'i 

Ans. When the indicator is not used in the cal- 
culation the boiler pressure is substituted for the 
mean effective pressure. Deduct from the result 
obtained from 40 to 60 per cent, for loss by conden- 
sation and friction of steam pipes and passages 



80 ENGINEERS' EXAMINATIONS. 

decrease of pxessure in cylinder due to expansion, 
back pressure of exhaust and friction of the working 
parts.* 

(Jues. How do you proceed with a compound engine ? 

Ans. By the same rule applied to each cylinder — 
adding the totals together gives the power of the 
whole. 

Ques. What are compound engines ? 

Ans. Compound engines are those which have 
two or more cylinders of successively increasing 
diameters so arranged that the exhaust steam from 
the first and smallest cylinder is passed forward to 
Jo work in a second cylinder before escaping to the 
condenser. 

Ques. What are the particular advantages claimed by 
compounding ? 

Ans. I, The compound engine enables the full- 
est advantage to be taken of the expansive power of 
very high-pressure steam ; 2, The ease with which it 
may be adapted to work on one or more cranks, 
thereby reducing the excessive variation of strain 
which occurs in a single cylindered engine using 
high pressure steam. 



*NoTE. — The mean pressure in the cylinder when cutting off at 

J4 stroke equals boiler pressure multiplied by .597 
Jl - - " " " " .670 

.743 
.847 
.919 
.937 



QUESTIONS AND ANSWERS. 81 



Ones. How may compoimd engines be classified ? 

Ans. Into those, i, where the piston of each 
cylinder commences the stroke at the same time ; 2, 
and those which exhaust from one cylinder before 
the next cylinder is ready 'to receive it ; in which 
case the steam is retained, for a portion of the 
stroke, in a chamber or receiver between the two 
cylinders. These are termed " receiver " engines. 

Ques. What is to be said about triple and quadruple 

expansion engines ? 

Ans. The principles which govern the construc- 
tion and management of the compound are the 
same in the triple and quadruple expansion engines, 
namely, those in which the steam is expanded in 
three or four cylinders respectivelv. These are the 
necessary outcome of increased pressures of steam ; 
for, since the terminal pressure is about constant, 
increased pressures involve an increased number oi 
expansions. And in order to prevent undue range 
of stress and temperature, three and even four cylin- 
ders are now employed.* 



* Thus the same reasons which led to the rejection of the single- 
cylinder engine in favor of the two-cylinder compound, have now led 
to the rejection of the two-cylinder engine (at least, in marine work), 
and the adoption of the triple-compound, and in some cases the 
quadruple compound in its stead. The steamer " Northwest "— 
Buffalo to Duluth— has engines of the quadruple cylinder type and 
are worked at 200 lbs. steam pressure, the cylinders being 25", 36", SiM", 
74" by 43" piston stroke, 120 revolutions, developing with ease 7,000 H. 
P. The screws (twin) are 13 feet diameter, 18 feet pitch, assuring 
speed of over 20 miles per hour: 



82 ENGINE AND BOILER F1THAQ& 



ENGINE AND BOILER FITTINGS. 



In the efficient operation of a steam plant, next to a well 
set boiler or boilers with a good draught, there conies an 
economical, strong and suitably proportioned engine — one or 
more. 

But, not less an importance and real necessity there must 
be the connections, fittings and appliances, in the selection of 
which equal care and good judgment must be brought into 
play. 

In the choice and arrangement of these fixtures the first 
thing to be observed is that they shall be of the very best of 
their kind as far as may be possible. 2d, each appliance 
should be in fair proportion to the other parts of the plant — 
neither too large nor too small, and 3d, they should be well 
and thoroughly ' ' fitted " — the skill of a good engineer Is 
shown in this as much as in setting a main valve or putting 
a ■ ' spectacle piece " on a boiler. 4th, every appliance should 
be kept in the best of working order and in the neatest con- 
dition with foresight also as to their giving away at an 
unexpected moment. 

The latter consideration implies the keeping on hand, as 
far as practical, of duplicates of all fittings and appliances, 
both in the engine and boiler rooms. Especially is this well 
where "the plant " is not in the vicinity of shops and supply 
housea 



QUESTIONS AND ANSWERS, 83 



Questions .and Answers relating to Engine 
and Boiler Fixtures. 

Ones. What are the principal belongings that are usually 
considered fixtures of a steam boiler ? 

Ans. The safety valve ; globe and check valves ; 
steam gauge ; the front, containing tube, fire and 
ash pit doors ; grate bars, with bearing bars ; dead 
plates ; man and hand hole plates and thimbles ; 
water gauge cocks and glass gauges ; blow-out 
apparatus ; fusible plug ; surface blow cocks with 
scum apparatus ; steam whistle ; and for the brick 
work, binder bars, anchor bolts, back stays, cleaning 
out doors, and lugs to support the boiler. 

Ques. What other appliances can you name necessary to 
complete the operation of a steam boiler ? 

Ans. The pump or injector ; the feed water 
apparatus with piping of various kinds ; the steam 
pipe (with globe valve) leading to the engine ; feed 
water heater; steam-trap; thechimney and damper; 
the fire-tools, flue brushes and scaling tools, with the 
hose to wash out the boilers ; water meters ; strain- 
ers and foot-valves for clearing the water before 
entering the boiler. 

Ques. What are thimbles in use on boilers ? 

Ans. These are the heavy castings riveted on 
the upper shell of the boiler with flanges planed to 
which to bolt the safety valves or pipe connections 
—a thimble in gas pipe definitions is " a connection." 



!1 ENGINEERS' Eli. AMI NATIONS, 



<^ueSo What is a globe valve ? 

Ans. A globe valve takes its name from its shape. 
It is a valve in a round chamber. 

(^ues. How should globe valves be attached ? 

Ans. So that the pressure comes under the valve, 
or at the side, for if the valve should become loose 
from the steam (which they often do) if the pressure 
is on top, there would be a total stoppage of the 
steam. 

Ques. What is a valve ? 

Ans. A valve has a seat and is generally turned 
by a circular handle fitted to the spindle — the best 
example of a valve is that of an ordinary house 
pump, where the valve opens upward to admit the 
water and closes downward to prevent its return. 

(^ues. What is a cock ? 

Ans. A cock is a valve but a valve is not a cock 
— the cock is a cone-shaped valve slotted and fitted 
with a handle — example : the try-cocks of a boiler 
are cocks with their openings in line with the blow- 
off pipes. 

(Jues. What is a relief valve ? 

Ans. It is a valve so arranged that it opens out- 
ward when a dangerous pressure or shock occurs. 

QueSo What is a back pressure valve ? 



I 



J 



QUESTIONS AND ANSWERS. 85 

Ans. These are ball (or clack) valves in a pipe 
which instantly assume the seat when a back press- 
ure occurs. Their name signifies their use — to 
maintain a constant back pressure in heating 
systems. 

(|ues. What is a three-way cock ? 

Ans. It is one having three positions in which to 
direct the fluid in three ways. There is also a three- 
way valve. ^ 

Ques. What is a check valve ? 

Ans. A valve placed between the feed pipe and 
the boiler to prevent the return of the water, and 
similar uses. 

Ques. What is a ball valve ? 

Ans. It is a valve occupying a hollow seat. 
These valves are raised by the passage of a fluid and 
closed by their own weight. 

(^ues. What is the throttle valve ? 

Ans. This is the valve used to admit steam to 
the engine and so used (in stationary service) to 
distinguish it from the main stop, valve located near 
the boiler — to throttle means to choke — hence the 
throttling of the steam. 

Ques. What is a reducing valve ? 

Ans. This is a pressure-regulating valve and 
designed to reduce the pressure from a high point 



ENGINEERS' EXAMINATIONS. 



in the boiler to a low one in a system of steam heat- 
ing. 

(Jues. How should steam valves be connected ? 

Ans. So that the valve closes, against the con- 
stant steam pressure. 

Ques. What will prevent cracking and pounding noises in 

steam pipes in steam heating '? 

Ans. A thorough drainage of the pipes. 

(Jues. In steam and cast iron pipe how is the diameter 
given in the tables ? 

Ans. By the internal diameter. 

Ques. And the diameter of boiler tubes ? 
Ans. By the external diameter 

Ques. How is the strength of steam pipes, elbows, tees, 
threads, etc. , calculated for the safe working pressure ? 

Ans. By the same rules that are used in figuring 
the strength, strains, etc., of the steam boiler. 

Ques. What factor of safety would be best in view of the 
small diameter of the pipes ? 

Ans. A tensile strength of 50,000 lbs. to the 
square inch may be assumed with safety with a 
factor of 4. 

(Jues, What would you do with rusted spots ? 

Ans. Regarding rusted spots or places where 
corrosion has taken place, the thickness of good 



QUESTIONS AND ANSWERS. 87 

iron remaining should be taken as the thickness of 
the pipe or fitting, although small places having an 
area of i square inch or less may be ignored so long 
as the original thickness of the material remains ; 
but where the corroded area exceeds this, full allow- 
ancs must be made, A number of small places 
corroded, pitted or grooved and closely connected, 
require that only the thickness of good iron remain- 
ing shall be considered as the thickness of the 
material. 

v^ues. What is the tensile strength of cast and malleable 
iron — of which connections are mostly made ? 

Ans. The mean tensile strength of cast iron is 
from 16,000 to 20,000 lbs. and a factor of safety of 4 
should be employed. The mean tensile strength of 
malleable iron ranges from 30,000 to 40,000 lbs., and 
unless tests are made to determine the strength it is 
better to assume the smaller number, allowing as 
before a factor of safety of 4. 

Ques. What is to be stated about the pipe threads ? 

Ans. The threaded portions of pipes and fittings, 
when the greater portion of the thread is entered 
and the joint made in a workman like manner, will 
have sufficient strength to withstand the strain on 
the same principle that the single riveted girth 
seams have sufficient strength to withstand the 
strain, even though the longitudinal seams of the 
boiler be double riveted. 



ENQlNEt^BS' EXAMWATtONS. 



Ques* In taking charge of a new steam plant what is the 
first thing an engineer should do ? 

Ans. Make himself familiar with tne water and 
steam pipes and office of the valves connected with 
such pipes. 

Ques. "What are the dead centres or dead points of an 
engine ? 

Ans. At two instants in each revolution, the 
direction of the crank coincides with the line of 
connection (or straight line joining the centre of the 
joints of the connecting rods.) The positions of the 
crank pins at those instants are called dead points, 
and they correspond to the ends of the stroke of the 
pistons when its velocity vanishes. 

(^iies. What means are provided to overcome the effects of 
these dead jjoints without jar or irregularity ? 

Ans. It is to diminish the irregular action caused 
by the existence of these dead points and also to 
facilitate the starting of engines when the crank 
happens to rest upon one of them that engines are 
combined by pairs or threes. 

Ques. V/hat other device is used to prevent in stationary 
engmes the fluctuations in speed caused by the dead centres 1 

Ans. The fly wheel. 

Ques. Why are they not used in marine and locomotive 
engines ? 

Ans. In marine service the propeller, whether 
paddle or screw, answers the purpose of a fly wheel; 
in locomotives the entire engine suffices to prevent 
excessive fluctuations. 



nrmsTioNs AND Asswmts. 89 

C|uestiojis and Answers Relating to the 
Safety Talve. 

Oues. What is a safety valve ? 

Ans. it is a bonnet or conical valve loaded with 
a weight equal to the greatest extra pressure likely 
to be exerted by the steam on the boiler. 

Ques. What is the particular office of the safety valve ? 

Ans. To relieve the boiler from a pressure which 
may become dangerous and cause an explosion. 

Ques. Is the sound of steam from a safety valve a sign of 
danger ? 

Ans. No, it is a token of safety ; it shows the 
valve to be in operation, and if properly set, a sure 
protection. 

Ques. What danger exists when a safety valve " sticks " 1 

Ans. The valve holds the pressure until it gets 
higher and higher, until so very high that the safety 
valve finally gives way and allows so much steam to 
escape at once that it changes the condition or 
balance of the steam and water inside the boiler, 
causing danger of an explosion. 

Ques. How should this be guarded against ? 

Ans. By raising the valve, when under pressure, 
once or twice a day — doing so very gently and 
gradually — to make sure that it is in working order. 



90 EHrOINEEES' EXAMINATIONS. 

Ques. When a safety valve is described as a 2 inch val\«e 
or a 23^ inch valve, what is indicated by the aescription i 

Ans. It means that 2 inches, or 2).^' inches is the 
diameter of the pipe. 

(^ues. What part of the boiler is preferable for the position 
of the safety valve ? 

Ans. It is best placed upon the boiler at the 
part furthest away from the water line, so as to be 
unaffected by the k aming of the water — if any exists. 

(jues. Is there more than one variety of the safety Valve? 

Ans. Yes. The Lever, or the common form, and 
the Spring loaded safety valve ; also the dead-weight 
safety valve. 

Ques. What is the "pop " safety valve ? 

Ans. It is a well-known form of spring valve 
and takes its name from the fact that it takes a little 
more pressure to raise it off its seat than what it is 
set at, consequently it releases itself with a "pop *' 

(^ues. What are the points of contact of a valve called ? 

Ans. The fixed part is called the seat of the 
valve and the part resting upon it is called the face 
of the valve. The seat is preferably adjusted at an 
angle of 45 degrees and the face made to fit. 

(^ues. What is the val ve spindle ? 

Ans. It is the small guiding rod which moves 
upwards and downwards with the face of the valve. 
Its office is to keep the two faces opposite and cause 
the rise and fall to be perfectly even and true. 



QUESTIONS AND ANSWERS. 91 

Ques. What are the most essential ]iroblems to be per- 
formed in reference to the steam plant, and why V 

Ans. Those relating to the safety valve ; because 
the safety valve is the most important fixture 
belonging to the steam boiler. 

Qiies. Why should the size of the safety valve bear a cer- 
tain proportion to the size of the boiler '? 

Ans. Because if the valve is too large it is liable 
to be blown off when raised by excessive pressure, 
and if too small then it will not relieve the boiler in 
time to prevent an explosion 

Ques. Can you give the rules for size best proportioned ? 

Ans. Rankine's rule for the dimensions of safety 
valves is : Multiply the number of pounds evaporated 
per hour by .006 and the product will be the area in 
square inches of the valve. The United States 
steamboat inspection law requires for the common 
lever valve one square inch of area of valve for every 
two square feet of area of grate surface. A rule 
adopted by the Philadelphia Department of Steam 
Engine and Boiler Inspection is : i. Multiply the 
area of grate in square feet by the number 22.5, 
2. Add the number 8.62 to the pressure allowed per 
square inch. Divide (1) by (2) and the quotient 
will be the area of the valve in square inches. 

Qnes. How would you figure for 36 feet of grate surface 
with 80 lbs. pressure ? 

Ans. 36 sq. feet of grate X 22.5 — 810.0, Press- 
ure allowed 80 lbs. + 8.62 = 8S.62; 810 -r- 88.62 = 
9.14 or a valve having a diameter of 3.4". 



92 ENQINEERS' EXAMINATIONS. 

I 

(Jnes. What three elements enter into each calculation 
relating to the safety valve ? 

Ans. I, The number of square inches on the face 
of the valve and the pressure of the steam ; 2, the J 
weight of the lever and valve in lbs ; 3, the amount ^ 
of the weight and its position on the arm of the 
lever.* 

Ques. How do you find the square inches of a valve, the |l 
diameter being known ? ^ 



Ans. By multiplying the square of the diameter 
of the circle by the decimal .7854. 

Ques. How would you figure the pressure on a 3 inch 
valve with 100 lbs. boiler pressure ? 

Ans. Thus — 3 X 3 = 9 in. 

9 X .7854 = 7.068 area, 
7.068 X 100 = 706.8 lbs. 

(Jues. What is the Lever and what are its essential points? 

Ans. Of the six mechanical powers (pully, v/heel, 
screw, etc.) the lever is the first in the list. 

There are three essentials in the lever — i, the 
fulcrum, or prop ; 2, the power; and 3, the weight; 
or, differently stated, i, the point on which the bar, 
or lever, turns (the prop, or fulcrum); 2, the place 



4 



* The weiglit of the lever and valve is of so little importance in the 
matter of pressure that examining engineers usually omit it from their 
questions. 



QUESTIONS AND ANSWERS. 93 

where the power is applied ; and 3, the point where 
the weight is applied.* 

Ques. How many classes or kinds of levers are there ? 

Ans. There are three classes of the lever, num- 
bered according to the relative position ot the 
fulcrum ; the safety valve lever is a lever of the third 
kind. 

Ques. What is the method of calculating the power of the 
lever ? 

Ans. The same calculation applies to each of 
the three classes of levers. 



w , '- 



-t 

^w' 



\ 



^ 



Rule for Calculating L^evers. 

The force (P) multiplied by its distance from the 
fulcrum (F) is equal to the weight (W) multiplied 
by its distance from the fulcrum. 

Note.— When two forces act upon each other hy means of any 
machine, that which gives it motion is called THE POWER, and that 
which receives, the weight (WEIGHT). See illustration. 

The calculations are to be made in inches for distances and in 
pounds for the forces and weights, and the calculations are made for 
the action of mechanical powers upon the supposition that their action 
is not affected by their own weight, or by friction and resistance. 

* In the safety valve lever the prop or fulcrum is the hinge-joint 
upon which the arm moves, the point where the power is applied is the 
conical valve being pressed upward by the steam, and the point where 
the weight is applied is oa the arm of the l^iver. 



94 



ENGINEERS' EXAMINATIONS. 



Ques. What rule of arithmetic can be used to advantage 
in working safety valve problems ? 

Ans. The rule of three or rule of proportion." 

\{ a J- ^t li^ 




Note.— In the illustration F is the fulcrum ; "V is the point where 
the pressure is exerted ; W is the weight ; FV is 6 inches ; and VW is 
10 inches ; therefore FW is 16 inches. 

Ques. When the length of the lever, the weight and 
length of the short arm are known, give the rule for finding 
the steam pressure the weight will hold, give both rule and 
example. 

Ans. Rule (One). 

Multiply the length of the lever by the weight and 
divide the product by the length of the short arm. 



* This " rule of three " is one of the most useful in the whole range 
of mathematics ; a rule by which, when three numbers are given, a 
fourth number is found. 



QUESTIONS AND ANSWERS. 95 



Example. 
The length of lever being 20 inches, the weight 20 
lbs. on the end of it, and the short arm being 4 
inches, then 

The length of the lever, 20 

Multiplied by the weight, 20 



Divided by the short arm, 4)400 



Answer, 100 lbs. resistance.* 

Ones. When tlie diameter of the valve, the steam press- 
ure, the length of the short arm and the weight are known, 
what is the rule to find the place to hang the weight '? Give 
rule and example. 

Ans. Rule (Two). 

Multiply the steam pressure in lbs. by the length 
of the short arm of the lever in inches, and divide 
the product by the weight of the ball. 

Example. 
The diameter of the valve being 2j4 with steam 
at 60 lbs. gives the resistance to be overcome (i. e., 
2.5 X 2.5 X. 7854 = 4/Tr area of valve multiplied by 60 
ibs ) 294 lbs.; the short arm of the lever, 3 inches; 
'.veight of ball, 40 lbs. Now then : 
The resistance (steam pressure) = 294 
The short arm, 3 

Divide by weight, 40)882 



22 05 inches of lever. 



■^ This 100 wonld represent a valve area of SJ.^ sq. in. at 40 lbs. press- 
are, etc. 



m ENGINEERS' EXAMINATIONS. 



Ques. When the steam pressure, the short arm, and the 
length of the lever are known, to lind weight of ball needed. 
Give rule and example. 

Ans. Rule (Three). 

Multiply the steam pressure by the short arm, and 
divide the product by the length of the lever, the 
answer is the weight of the ball. 

Example. 
The steam pressure (as in the last example) being 
294, the short arm 2 inches, and the length of the 
lever 30 inches. Now then : 

The steam pressure, 294 

Multiplied by the short arm, 2 

Divided by the lever, 30)588 

Weight of ball needed, 19.O lbs. 

Ques. When the weight, length of lever and the steam 
pressure (resistance) are knoM-n, to find the length of the 
short arm. Give rule and example. 

Ans. Rule (Four). 

Multiply the length of the lever by the weight and 
divide the product by the steam pressure. 

Example. 
The lever being 20 in., weight 20 lbs., steam pres*;- 
ure 100 lbs. Now then : 

Length of lever, 20 

Weight, 20 

Divide by steam pressure, 100)400 

Length of short arm, 4 inches * 



* This 100 represents the total steam pressure on the valve— tlie 
s'yaraple given being the reverse of the one for rule one. 



QUESTIONS AND ANSWERS. 97 



Ques. If the ball is removed from the lever can there Iw 
any steam pressure on the boiler ? 

Ans. Yes ; that due to the weight of the valve 
and stem. If they weigh, say 2 lbs., and the area of 
the valve is 7 sq. inches, then that would cause a 
pressure of f of one lb. before the steam blows off. 

Ques. What about the lever itseK ? 

Ans, The weight of the lever also operates the 
same way, except it is not a dead weight. 

Ques. Explain why it is not a dead weight. 

Ans. If you have a lever 30 inches long and it 
has the same size from end to end, its balancing 
center will be in the middle, or 15 inches. If the 
lever (bar) weighs 8 lbs. it will have the effect of 
hanging a ball of 8 lbs., 15 inches from the fulcrum. 

Ques, Is there anything else which should be thought of 
in figuring the safety valve problems ? 

Ans. Yes, a possible difference in the true 
diameter of the valve or connection pipes — the 
opening of the valve may be 2 inches diameter, but 
the circle of contact of face and seat may be 2)4 — ■ 
this would make a difference of nearly j4 sq inch of 



area. 



* This diflEerenoe need not be considered important in view of tho 
factor of safety (6) usually allowed, i. c, the boiler is made to with- 
stand six times the ordinary pressure : But, it bears upon the questio'a 
of omitting the weight of valve spindle and lever from comirtoa calcu- 
lations. 



98 



ENGINEERS' EXAMINATIONS. 



Table of Properties of Saturated Steam. 



Absolute 

pressure 

in lbs. per 

sq. in. 


Tempera- 
ture Fah. 


Total beat of 

evaporation 

from water at 

33° F. 


Volume 
per lb. in 
cubic feet. 


1 


103.0 


1113.0 


330.36 


2 


136.4 


1130.5 


173.08 


3 


141.6 


1135.1 


117.52 


4 


153.1 


1128.6 


89.62 


5 


163.3 


1131.4 


72.66 


6 


170.1 


1133.8 


61 21 


•? 


176.9 


1135.9 


52 94 


8 


183.0 


1137.7 


46.70 


9 


188.4 


1139.4 


41.80 


10 


193.3 


1140.9 


37.84 


11 


197.8 


1143.3 


34.63 


12 


203.0 


1143.5 


31.90 


13 


305.9 


1144.7 


29.57 


14.7 


312.0 


1146.6 


26.36 


15 


213.1 


1146.9 


35.85 


16 


216 3 


1147.9 


34.32 


17 


219.5 


1148.9 


22.96 


18 


333.5 


1149.8 


21.78 


19 


235.3 


1150.6 


20.70 


30 


238.0 


1151.5 


19.72 


31 


230.7 


1152.3 


18.84 


22 


233.3 


1153.1 


18.03 


23 


235.8 


1153.9 


17.26 


24 


238.2 


1154.6 


16.64 


25 


240.5 


1155.3 


16.00 


36 


242.7 


1156.0 


15.38 


27 


244 8 


1156.6 


14.86 


38 


246.8 


1157.2 


14.37 


29 


248.7 


1157.8 


13.90 


80 


250.5 


1158.3 


13.46 



QVESTIONS AND ANSWERS, 



99 



Table of Properties of Saturated Steam. — Continued."^ 



Absolute 

pressure 

in lbs. per 

sq.. in. 


Tempera- 
ture Fah. 


Total heat of 

evaporation 

from water at 

32° F. 


Volume 
per lb. in 
cubic feet. 


35 


259.3 


1161.0 


11.65 


40 


267.0 


1163.4 


10.28 


45 


274.4 


1165.6 


9,18 


50 


281.0 


1167.6 


8 81 


55 


287.1 


1170.0 


7.61 


60 


292.6 


1171.2 


7.01 


65 


298.0 


1172.7 


6.49 


70 


302.8 


1174.3 


6.07 


75 


307.5 


1175.7 


5.68 


80 


312.1 


1177.1 


5.35 


85 


316.1 


1178.4 


5.05 


90 


320 3 


1179.6 


4.79 


95 


324.1 


1180.8 


4.55 


100 


827.7 


1181.9 


4.33 


105 


331.3 


1182.4 


4.14 


110 


334.6 


1184.0 


3.97 


115 


338.0 


1184.5 


3.80 


120 


341.1 


1186.9 


3.65 


130 


347.2 


1187.9 


3.38 


140 


352.9 


1189.6 


3.16 


150 


358.3 


1191.2 


2.96 


160 


363.4 


1192.8 


2.79 


170 


368.3 


1194.3 


2,63 


180 


383.0 


1195.7 


2.49 


190 


377.5 


1197.1 


2.37 


200 


381.8 


1198.4 


2.26 


250 


400.8 


1204.2 


1.83 


300 


417.1 


1209.2 


1.54 


350 


430.1 


1212.2 


1.33 


400 


445.0 


1217.7 


1.18 



Lcf 



♦ Regnault. 



iOO SATURATED STEAM. 



SATURATED STEAM. 



This has been defined on page 59 as tlie steam wliicli rests 
upon the water witliin a boiler under pressure. Attention is 
no'w invited to tlae Tables (Regnault's) on the two preceding 
Images. 

Let water at 32° be heated in a closed vessel, such as an 
ordinary steam boiler, containing space for the accumulation 
of steam, and let heat be gradually applied. Then the tem- 
perature of the Avater will gradually rise, and steam will be 
formed. 

As the heat is increased, the temperature, pressure, and 
density, or weight per cubic foot, of the steam increase 
indefinitely, so long as the strength of the boiler is not 
exceeded ; and the relation bet^veen the tempei'ature, press- 
ure, and density always bears a certain fixed relation. 

If heat is applied so as to maintain the temperature con- 
stant, the pressure and density remain constant also, and 
evaporation ceases. If a communication be opened between 
the boiler and engine, on escape of steam from the boiler the 
pressure is momentarily reduced and re evaporation com- 
mences rapidly. So long as the temperature is maintained, 
no sensible variation of pressure is noticeable in a boiler sup- 
plying steam to an engine. 



SATURATED STEAM. ]01 



It will be observed from the tables that saturated steam 
under a given pressure has a fixed temperature, also that the 
temperature and density increase with the pressure. 

But it will be further noticed that the total heat increases 
in a very £.low ratio compared with the pressure and temper- 
ature, there being only a very small increase of total heat 
per lb. of steam as the pressure increases. This is an 
important point in practice when considered in reference to 
coal consumption, for it shows that it is not much more 
costly in fuel to generate high-pressure steam than low- 
pressure steam, weight for weight ; and that far more work 
can be obtained from it when used expansively than from 
the same weight of low-pressure steam — hence the economy 
of high-pressure steam. 

In this connection it is interesting and important to com- 
pare the difference in the weight of water requu-ed to cool a 
given weight of water, with that required to cool the same 
weight of steam at the same temperature. 

This is owing to the mysterious element which exists in 
steam under pressure — very like the unknow-n essential prop- 
erty of electricity — called latent heat. In generating water 
into steam there is absorbed about five and one-half times as 
much heat as is required under atmospheric pressure, to 
raise the temperature of the water from freezing point, 32° 
F., to boiling point, 212° F., an amount of heat which 
if the v^ater were a fixed solid %vould, it is said, render it red 
hot by daylight. Tested by a thermometer the steam will 
show only 212°, but by experiment 1000°, nearly, have been 



102 



SATURATED STEAM. 



added, which is stored up in some hidden unaccountable 
way ; this is called the latent heat of steam. 

There are two sorts or conditions of heat in the process of 
steam production operating upon "water : 1, Sensible heat; 2, 
Latent or insensible heat ; hence the constituent or total 
heat of steam consists of its latent heat in addition to its 
sensible heat. 

The appropriation of the heat expended in the generation 
of one pound of saturated steam at 212° F. , from water sup- 
plied at 32° F., may be exhibited thus : — 

To Generate one Pound of Steam at 212° F. 





Units of heat. 


Mechanical equiva- 
lent in foot-pounds. 


The sensible heat : — 






1. To raise the tempera- 






ture of the water 






from 3-3° to 212° F., 


180.9 


139,655 


The latent heat:— 






2. In the formation of 






steam 


892.935 


689,346 


3. In resisting the incum- 






bent atmo spheric 






pressure of 14.7 lbs. 






per square inch, or 






2116.4 lbs. per square 






foot 


72.265 


55,788 




965.2 


7'l'i 1^^ 




'^^^^^^ Jrrcl, Xt>*± 


Total or constituent heat. . . 


1146.1 


884,789 



Ques. What is the rule for finding the total heat in steam V 

Ans. Multiply temperature or sensible heat of 
the steam by .3 (1%) and add it to 1115°. 



SATURATED STEAM. 103 

C^ues. Give an example. What is the total and latent 
heat in steam that is 100 lbs. by the gauge ? 

Ans. loo lbs. by the gauge is 115 gross, the 15 
being, approximately, the weight of the atmosphere, 
and 115 gross has (by Table page 99) 338° of heat, 
hence, 

338 X .3 = 101.4 + 1115° = 1216.4 = total heat. 

338.0 = sensible heat 



8781% latent heat* 

Ques. What are the total units of heat in steam of 213° ? 
Ans. 2i2°x. 3 = 63. 6+1115° = 1178.6° total heat 

(^ues. What is the latent heat in this case ? 
Ans. 1 1 78.6 = total heat. 

212 == sensible heat. 



966.6 = latent heat. 

Ques. If the temperature of the feed water is known, what 
will be the number of units of h>eat to each lb. of water 
turned into steam ? Give illustration. 

Ques. If the steam in the boiler be 270° and the feed water 
be at 110° how^ many units of heat will it be necessary to add 
to tliis water to turn a lb. of it into steam ? 

Ans. 270 X. 3 = 81 4-1115 = 1 196, less feed water 
110^1086. 



* The small variation between the results in the examples and the 
figures in the Table is caused by greater detail of calculation in one 
more than the other. In the examples the air pressure is extended at 
15 lbs. per square inch and in the Tables at l-t.T. 

Let it be remembered that a Thermal unit (expressed by T. U.) is 
the raising of 1 lb. of water 1 degree, and that the mechanical force 
existing in each unit is 772 lbs. 



104 EiSrOiNEiEB''S EXAiUmATIONS. 

Ques. "Which conducts heat best, dry steam or cloudy 
steam ? 

Ans. Dry steam is a poor conductor of heat as 
compared with either liquid water or cloudy steam, 
for after cloudy steam has received heat enough to 
make it dry or nearly dry it receives additional heat 
very slowly. 

Ques. If a steam jacket is used, is the steam in the cylin- 
der affected by the heat of the steam in the jacket ? 

Ans. It is assumed that the steam in the cylinder 
while expanding, receives just enough of heat from 
the steam in the jacket to prevent any appreciable 
part of it from condensing without superheating the 
steam in the cylinder. 

Ques. Is there any gain in using steam at 100 lbs. and by 
expansion making the mean effective pressure 70 lbs. over, 
using steam of 70 lbs. throughout the entire stroke ? 

Ans. Using a cylinder with a volume of i cubic 
foot, and an initial pressure of 70 lbs. continued 
throughout the stroke, would be using, at each stroke, 
a cubic foot of 70 lb. steam, or a weight of ,201 of a 
pound. Now, should the initial pressure be 100 lbs., 
a cut-off at ys stroke would give the desired mean 
effective pressure of 70 lbs. and only use ^ cubic 
feet of steam. Now, 100 lbs. steam weighs .264 lb. 
per cubic foot ; ^ cu. ft. therefore = .099, so that 
only .099 lb. would be used against .201 lb. of the 
lever pressure steam, as in the first case. Thus by 
working steam expansively you have a gain of 
.20I — .099 ==.102 lb. at each ^ stroke. 



PUMPS. 105 



PUMPS. 



Upon the uniform operation of the pump depends the 
safety and comfort of the engineer, owner and employees, 
and indirectly of the success of the business with which ' ' the 
plant " is connected. 

Pumps now raise, convey and deliver water, beer, molasses, 
acids, oils, and melted lead. They also handle such gases as 
air, ammonia, lighting gas and even oxygen. 

Pumps are made in various forms and sizes ; they vary in 
design to suit their several uses, and are defined as rope, 
chain, diaphram, jet, centrifugal, rotary, oscillating, cylin- 
der. 

It is with the last named class "with which the engineer 
has principally to become expert. Cylinder pumps are of 
two kinds, single acting and double acting. 

The feed pump is used to supply the boiler, and it is 
required to supply a quantity of water at least equal to that 
evaporated and passed forward to the engine, together with 
leakage at safety valve, &c. ; and to provide also for emer- 
gencies it is usually made capable of supplying from 2 to 2^ 
times this quantity. 



106 



PUMPS. 



The action of the pump may be explained as follows : Sup- 
pose the plunger P at the bottom of its stroke, and the whole 
interior of the pump to be full of air. When the plunger 
rises the pressure of the suction valve S will be reduced, and 
the air in the supply pipe will lift the valve and flow into the 
barrel. The pressure of the air in the supply pipe is now less 
than before, and accordingly the pressure on the external 
surface of the wa- 
ter forces water up 
the pipe to such a 
height as to make 
the pressure inside 
the pipe balance the 
pressure outside. 
When the plunger 
returns the suction 
valve is closed by 
the pressure, and 
the air is forced out 
through the deliv- 
ery valve D. Each 
time the stroke of 
the plunger is re- 
peated, the water 
will rise in the sup- 
ply pipe until at last it reaches and fills the barrel. Now, 
when the plunger returns, it forces water instead of air 
through the delivery valve. 

The height of the column of water which will balance the 
pressure of the atmosphere is o4 ft. ; that is, a column wliose 




-te 



THE PUMP. 



PtJMPS. 107 

weight is about 15 pounds per sq. in. In practice, however, 
the supply can never be drawn from a depth greater than 
about 25 ft. 

The valves are prevented from rising above a certain height 
by stops shown in the figure. The lift of a valve should not 
exceed one-fourth of its diameter, for with this lift the whole 
of the water which passes through the valve seating can 
escape freely round the edge of the valve. Any further lift 
is therefore unnecessary. 

Air vessels A, V, are chambers fitted to pumps close to and 
beyond the delivery valve. The air in the water collects in 
this vessel and forms a cushion or spring which enables the 
water to be delivered in a steady stream. 

Ques. What is a single acting pump ? 

Ans. A single acting pump does its work through 
one end of the cylinder. 

Ques. What is a double acting pump ? 

Ans. It is an engine and pump combined ; in 
double acting pumps the motion of the piston in one 
direction causes an inflow of water, and a discharge 
at the same time, in the other ; and on the return 
stroke the action is renewed as the discharge end 
becomes the suction end. The pump is thus double 
acting. 

Qnes. In a steair pump what are the two ends called ? 

Ans. The steam-end, which is a complete steam 
engine, and the water-end, into which the water is 
drawn, and from which it is discharged. 



108 ENGINEERS' EXAMINATIONS. 

Ques. What is the connection between these ends — if any ? 

Ans. The water and steam ends are operated by 
a single rod, called the piston rod, which extends 
through from one end to the other — a pump so 
operated is a direct acting steam pump. 

Ques. What is the force against which a pump works 
aside from the boiler pressure ? 

Ans. Gravity, or the attraction of the earth, 
which prevents the water from being lifted. This is 
shown in the fact that water can be led, or trailed 
an immense distance, limited only by the friction, 
by a pump. 

Ques. What is the difference between a suction and a 
discharge valve ? 

Ans. The suction valve prevents the return of 
the water after it has entered the cylinder, and the 
discharge valve permits the outward passage of the 
water but does not allow its return. 

Ques. Is it true that water is raised by suction ? 

Ans. No. Water is raised by pressure of air on 
the water outside the pump. The piston of the 
pump exhausts the air and the unbalanced weight of 
water causes it to rise within the pump or pipes 
supplying the pump. 

Ques. What is the limit of this lift 7 

Ans. About ^2 feet, because water of one inch 
area weighs 14^5 lbs., which is the weight of one 



QUESTIONS AND ANSWERS. 109 



'nch of air, at the sea level. Pumps must be in 
good order to lift 33 feet, and all pipes and valves 
must be perfectly air tight ; pumps will give better 
satisfaction lifting from 22 to 25 feet. 

Qiies. In designing or purchasing pumps what is the safe 
rule as to capacity ? 

Ans. One should be selected capable of deliver- 
ing one cubic foot of water per horse power per 
hour ; or say, three pounds of water for each square 
foot of heating surface. 

Ques. Why will not a pump lift hot water ? 

. Ans. Because the vapor from the hot water fills 
the vacuum as fast as it is made by the piston and 
destroys its force, hence, no pump, however good, 
will lift hot water. 

Qiies. What is the best method of getting around this 
difficulty ? 

Ans. The pump should be placed below the 
supply, so that the water may flow into the valve 
chamber. 

Ques. What is the most necessary condition for the satis- 
factory operation of a pump ? 

Ans. A full and steady supply of water. The 
pipe connections should in no case be smaller than 
the openings in the pump, and the suction lift and 
delivery pipes should be as straight and smooth on 
the inside as possible. 



110 ENGINEERS' EXAMINATIONS. 

Ques. What is the advantage of the suction chamber ? 

Ans. It prevents pounding — makes the action of 
the pump easy and uniform and enables the pump 
barrel to fill when the speed is high. 

(^ties. How should pumps be left in cold weather ? 

Ans. Pumps should always be drained in cold 
weather, as freezing of water in pipes or cylinders is 
sure to burst them. Engineers should therefore be 
careful, and open the drip plugs or cocks, which are 
provided on all pumps for draining them. 

Ques. What directions would you give as to setting up a 
pump ? 

Ans. Use as few bends and valves as possible, 
and run every pipe in as direct line as practicable, 
and where convenient use full round bends rather 
than elbows, for valves, returns and elbows increase 
friction more rapidly than length of pipe ; never use 
pipes too small in diameter ; in long pipes this 
should be increased to allow for increased friction, 
especially in suction pipes. 

Ques. In ordering a pump what is it for the interest of the 
purchaser for the builder to know ? 

Ans. ist. For what purpose is the pump to be 
used, and the average pressure of steam ? 

2d. What is the liquid to be pumped, and is it hot 
or cold, clear or gritty, fresh, salt or acidulous? 

3d. What is the maximum quantity to be pumped 
per hour ? 



QUESTIONS AND ANSWERS. Ill 

4th. To what height is the liquid to be lifted by- 
suction, also the height of discharge ? What are the 
length and diameter of the suction and discharge 
pipes, and the number of elbows or turns ? 

Qucs. Granted motion to the piston or plunger of a pump 
what is the only cause that makes it fail with an abundance 
of water ? 

Ans. A pump fails because it leaks — there can 
be no other reason, and the leak should be found 
and repaired. Leaky valves are common and should 
be ground ; leaky plungers are frequent and should 
be re-turned in a lathe ; leaky pistons sometimes 
exist and they should be repaired. The rod must be 
straight as far in as the packing and that must be 
kept free from dirt and sediment. 

Ques. What should long suction pipes be provided with ? 

Ans. A foot valve, just above the strainer, in the 
well or pit. 

Ques. What are direct acting steam pumps ? 

Ans. These have a single cylinder non-expanding 
and in larger sizes with double cylinders on the 
compound principle. These pumps may be divided 
into two classes ; those having the valve gear on the 
outside where it can be seen, and those having the 
valve gear inside, no moving parts being visible 
when the pump is in operation except the piston 
rod. 

Ques. What are direct acting duplex pumps ? 



113 ENGINEERS' EXAMINATIONS. 

Ans. These are two steam pumps placed side by 
side, so combined that the slide valve of each 
cylinder gets its motion from the opposite piston 
rod through a lever and rockshaft. The single 
direct acting and the duplex direct acting pumps 
are almost always double acting pumps, having the 
steam piston and the water piston at the two ends 
of the same rod. Therefore the steam pressure 
exerted upon the steam piston will be exerted upon 
the water piston direct. 

(Jues. What are pumping engines ? 

Ans. It has become customary to apply the term 
pumping engines to large reciprocating pumps used 
for supplying cities and towns with water,- draining 
lakes and marshes, and other purposes, although 
strictly speaking any steam pump with its motor 
arranged in one machine is a pumping engine. 

Ques. "Which should have the larger area, the steam pis- 
ton or water piston of the steam pump ? 

Ans. The steam piston should have about 2^ 
times the area of the water piston. There being no 
mechanical purchase in favor of the steam piston, it 
must have the greater area of the two, otherwise 
the pressure on the water piston would equal the 
pressure on the steampiston and the pump would 
refuse to work. For this reason all boiler pumps 
have larger steam pistons than water pistons. 

Ques. What rule would you give for area of steam piston ? 
Ans. Multiply area of water piston by 2.75. 



QUESTIONS AND ANSyVERS. 113 

Qlies. How woiild you find the capacity of a water 
cylinder of a steam pump in gallons ? 

Ans. Multiply the area in inches by the length 
of stroke (this gives the capacity in cubic inches). 
Next divide by 231 (which is the cubical contents 
of a U. S. gallon) and the product is the capacity in 
U. S. gallons. 

Ques. What is the rule for finding quantity of water 
pumped in one minute running at 100 feet of piston speed 
per minute ? 

Ans. Square the diameter of the water cylinder 
in inches and multiply by 4. The answer will be in 
gallons. 

(^ues. How do you find the horse-power necessary to 
pump w^ater to a given height ? 

Ans. Multiply the total weight of the water in 
pounds by the height in feet and divide the product 
by 33,000. 

Ques. How do you find the pressure in lbs., per square 
inch, of a column of water ? 

Ans. Multiply the height of the column of water 
in feet by .434. 

Ques. What is the rule for finding the water capacity of 
a steam pump per hour ? 

Ans. ist. Find the capacity of the pump in cubic 
inches, by multiplying the area by the inches in 
Strokes, and by the fraction it is full. 



114 ENGINEERS' EXAMINATIONS. 

2d. Find the cubic inches of water pumped per 
hour, by multiplying the contents of the pump by 
the strokes per minute and by 60, representing the 
minutes in an hour. 

3d. Find the number of the cubic feet of water by 
dividing the cubic inches by 1,728, 

Ques. In these rules have you made any allowance for 

" slippage " and friction ? 

Ans. No. 

Ques. What must every feed pump be designed to do ? 

Ans. It must provide not only the water really 
needed for the work, but a large percentage addi- 
tional to cover waste due to priming, condensation 
in the pipes, etc. 

Ques. Give an idea of amount of slippage ? 

Ans. In well designed and well constructed 
steam pumps the "slippage" will be one-tenth and 
an allowance of one-quarter will be safe for the 
friction ; but if the pump is old or badly designed 
or if the pump is working against a very high or a 
very low lift the net loss should be increased to 
twice the percentages given. 

Ques. Can you give approximate rule for size of pipes for 
steam ? 

Ans. For the steam pipe divide the area of steam 
piston by 64, 



QUESTIONS AND ANSWERS. 115 

For the exhaust pipe divide the area of steam 
piston by 32. 

For the discharge pipe divide the area of plunger 
by 3- 

For the suction pipe divide the area of plunger 
by 2. 

But as the sizes of piping are of standard sizes, 
sizes can only be approximated, preference being 
given to the next size larger than the figures call for. 

Ques. When pressure per square inch is shown by the 
guage, which is the greater pressure, that of water or steam? 

Ans. There is no difference between the intensity 
of steam pressure and water pressure, a pound of 
pressure is a pound whether of steam or water. 

Oues. What are pump valves made of ? 

Ans. They are made of brass, hard rubber, soft 
rubber, vulcanized fibre and wood. 

Ones. What is to be said as to their size and " lift " ? 
Ans. The valves should be larger than the pipe, 
enough so as to give a clear waterway, the same area 
as the suction pipes. The lift of the valves should 
be as little as possible without causing too much 
frictional resistance to the water. 

Ques. For leakage of water and steam priming, blowing 
off, loss by safety valve, etc., how much water for a station- 
ary engine should be provided ? 



116 ENGINEER'S EXAMINATIONS. 

Ans. From double to two and one-half times the 
net feed water required by the engines. 

(^iies. How much should be allowed in marine engines ? 

Ans. To provide for the discharge of the brine, 
from three to four times of the net feed water should 
be provided. 

Ques. Of what is water composed and in what proper 
tions? 

Ans. Water is composed of one volume of 
hydrogen to two of oxygen. 



Ques. What are the cubic contents and weight of a cubic 
foot of water ? 

Ans. I cubic foot equals 7^ gallons (1,728 cubic 
inches) and weighs 62^ lbs. A gallon thus has 231 
cubic inches and weighs 8^ lbs. 

Ques. What is the rule for finding the water capacity of 
the horizontal steam boiler 1 

Ans. I. Multiply two-thirds of the area of the 
head, in inches, by the length of the boiler in inches. 

2. Deduct the area of a single tube multiplied by 
the number in the boiler, multiplied by the length 
in inches. 

3. Divide by 231 to reduce the answer to gallons. 



QUESTIONS AND ANSWERS. 11? 



THE INJECTOR OR INSPIRATOR. 



This boiler fixture was an invention of Gifford, and is one 
of the most peculiar and interesting appliances connected 
with the steam plant. 

It is simply an instrument for allowing steam to rush from 
a boiler, and to suck up and mix with itself a stream of cold 
water, by which it is condensed, and to which it imparts so 
much of its own velocity, that the combined mass of water 
and condensed steam enters into and feeds the boiler. 

Injectors are used also to pump out cisterns and drain 
basins and have even been used to pump out mines. 



Questions and Answers Relating to the 
Steam Injector. 

Ques. What is the main difference between the steam 
pump and the injector ? 

Ans. The pump has moving parts and is a regu- 
lar machine, while the injector has no moving 
mechanism whatever. 

Ques. Whence comes the power, used in forcing water 
into the boiler by an injector ? 



118 ENGIJSrEERS' EXAMltfA'nOJSIii. 

Ans. To the difference in the velocity of the 
escaping steam from a boiler under pressure and the 
velocity acquired by water from the same boiler and 
under the same pressure and at the same time. 

Ques. About what is the difference in the speed of tL:6 
two? 

Ans. The steam has a velocity of sixteen or 
eighteen times that of the water — this varies with 
the pressure. 

Ques. How should the instrument be connected ? 

Ans. It should be so placed that it will take 
steam from the highest point in the boiler. A valve 
should be put in the steam pipe just above the 
injector and a check and globe valve between it and 
the boiler, also a globe valve in the supply pipe ; if 
the feed is delivered through a heater, place a check 
between it and the injector. It is better to have the 
suction pipe one size larger than the connection 
with the boiler, especially in case of a high lift. 

Ques. What are essential to the snccessful operation of 
the instrument V 

Ans. The suction pipe should oe absolutely air. 
tight ; the lift should not exceed 25 feet with a 
temperature of about no degrees and not more 
than 140 degrees for a low lift, 

Ques. Will the injector work if the water supplied to it is 
too hot '? 



QUESTIONS jLNJD a.kswi:rs. 119 

Ans. No. Because the colder the water the 
quicker and more thoroughly is the steam turned 
into water of condensation ready to join in the flow 
towards the boiler. 

(Jues. Dvjes the injector "suck up" or lift the water that 
it forces into the boiler ? 

Ans. No more than a pump does ; for both appa- 
ratuses simply remove the air from the supply pipes 
and the weight of the atmosphere pushes the water 
forward. 

Ques. What are injector-nozzles ? 

Ans. They are tubes with ends rounded to 
receive and deliver the fluids with the least possible 
loss by friction and eddies. 

Ques. What are double injectors ? 

Ans. They are those in which the delivery from 
one injector is made the supply of the second. The 
double injector makes use of two sets of nozzles, the 
"lifter" and "forcer." The lifter draws the water 
from the reservoir and delivers it to the forcer, 
which sends it into the boiler. 

Ques. What is the exliaust steam injector ? 
Ans. It is different from others in that it uses 
the exhaust steam from a non-condensing engine. 

Ques. What has been tlie objection to tlie greater adoption 
of this form of injector ? 

Ans. It carries over into the boiler the waste 
steam from the cylinder. 



120 ENGINEERS' EXAMINATIONS. 



THE INDICATOR. 



This device, inv^ented by James Watt more than a century 
ago, is an ingenious tell-tale of what goes on in the steam- 
cylinder. A knowledge of its operation is necessary to 
obtain a high-grade license. 

All indicators are practically of the same construction and 
act upon the same principle. Each consists of a small 
cylinder accurately bored out and fitted with a piston capable 
of working in the cylinder with Uttle or no friction ; the pis- 
ton rod is attached to a pair of light levers, at the end of one 
of which is carried a pencil designed to move perpendicu- 
larly. The motion of the piston in the cyUnder is |f of an 
inch and the area of the piston is exactly 3^ square inch. 

The pressure of the steam is recorded by the pencil at all 
points of the stroke as the piston moves to and fro, on a 
piece of paper secured to a revolving drum. The motion of 
the piston is controlled by springs of known tension, several 
of which are furnished with each instrument ; each spring is 
marked to show at what boiler pressure of steam it is to be 
used. 

The only absolute information any indicator can convey, 
whatever its form, is the pressure in the cylinder of the 
engine ; all the other information to be had from it comes 



QUESTIONS AND ANSWERS. I2l 

through a process of reasoning based upon experience and 
observation. 

In order that the diagram should be correct it is essential, 
first, that the motion of the drum and paper shall coincide 
exactly with that of the engine-piston, and that the motion 
of the pencil shall also correspond with the other motions 
described. 



Questions and Answers Relating to the 
Indicator. 

Ques. What is an indicator card ? 

Ans. It is a paper wound round the cylinder of 
the indicator upon which the pencil has drawn the 
lines indicating the work done by the steam in the 
cylinder. The extreme length of the diagram may 
be 5^ inches. 

Ques. What is the steam-line ? 

Ans. It is the line on the card which shows the 
place of admission to beginning of cut-off. 

Ques. What is the exhaust line ? 

Ans. It is that part of the diagram which shows 
the point of exhaust. 

Ques. What is the expansion line ? 

Ans. It is that part showing the curve of 
expansion; /. e., the movement between the cut off 
and the exhaust. 



122 ENOmWEnS' EXAMINATIONS. 

(|ues. What base line is always assumed in figuring the 
indicator card ? 

Ans. All figures are made from absolute vacuum, 
or 141V lbs. per sq. inch below atmospheric pressure. 

Ques. Why? 

Ans. For, from the line of absolute vacuum are 
made up all tables of weight, volume, expansion 
and all other properties of steam. 

Ques. What four points does an indicator show ? 
Ans. Highest and lowest pressure, cut-off and 
lead. 

Ques. How can you determine whether the steam is 

"wire-drawn " ? 

Ans. If the steam is " wire-drawn " the steam 
line will fall as the piston advances. 

(Jues. What is done when steam is cut-off at 6 inches ? 

Ans. When the piston has travelled 6 inches the 
valve closes, cutting off the live steam, and the 
remainder of the work in the cylinder is done by 
the expansion of the steam previously admitted. 

Ques. What do you understand by the number of an 
indicator spring ? 

Ans. The number marked on a spring (several 
of which are furnished with each indicator) is 
designed to show the number of lbs. steam pressure 
on the boiler at which it is to be used : thus a 30 lb. 



QUESTiOH^S AKn ANSVTWRS. l^B 

spring is one in which a pressure of 30 lbs. will 
cause the piston inside the indicator to rise one 
inch above the atmospheric line of the diagram.* 

Ques. What is an indicator diagram ? 

Ans. It is the figure drawn by the pencil attached 
to the indicator from which the mean effective 
pressure in the cylinder is calculated. 

Ques. How is this done ? 

Ans. By first dividing the diagram into ten equal 
spaces by drawing perpendicular lines to the atmos- 
pheric line called ordinates. Any number of ordi- 
nates may be used but it is customary to use 10. 

2. The two end ordinates should be only half the 
distance from the ends of the diagram that they are 
from the next ordinate, because the ordinate is the 
middle of the space it occupies. 

3. The ordinates being drawn their lengths are 
added together and the sum so obtained is divided 
by the number (10) which gives the average heighth. 

4. If a 30 lb. spring has been used and the average 
heighth of the ordinates is i^ inches, then the 



* The strength of the spring is so adjusted as to cause the diagram 
tobeahout2}4 inches high, let the steam pressure be what it may. 
The following are the scales of springs to he used in the Thompson 
Indicator : 

Scale of Used for pressure above atmosphere 

Spring- if not more than 

15 lbs. ... 31 lbs. per sq. in. 
80 " ... 38 " " " " 

80 " ... 94 » '' " " 
60 ** . . . 143 " " " " 



124 ENOTNEERS' EXAMINATIONS. 

average pressure of steam in the cylinder shown by 
the diagram is 45 lbs. 

Ques. Having found the average pressure in the cylinder, 
how do you proceed to get the indicated horse power (I. H. P.) ? 

Ans. By multiplying the travel of the piston in 
feet and the area of the piston in inches; 2, multi- 
plying the product by the mean average pressure in 
lbs. — in the case given ; 45 lbs. — and dividing by 
33,000. 

Ques. What have you to say as to calculating, by the 
indicator, the amount of water and steam used from the 
boiler ? 

Ans. Experience shows that the full amount of 
water used cannot be accounted for, owing to its 
being unduly saturated, the cooling of the cylinder, 
etc., hence the calculations made are unsatisfactory. 

Ques. Is there an easy way of getting the lengths of the 
ordinates ? 

Ans. Yes. Take a long strip of paper, say half 
an inch wide and 10 or 20 inches long, according to 
the nature of the card, mark a starting place on the 
edge near one end; then lay the strip of paper along 
the first dotted line, and mark off the length of that 
line ; then lay it on the second space so as to add 
the length of the second line to the first line; and so 
on until the tenth (dotted line) ordinate is added, 
the whole being in one length, end to end. 

Now take a rule and read off how many inches 
there are in the whole length, and divide them by ten. 



QUESTIONS AND ANSWERS. 135 



Qiies. What instrument has been invented and introduced 
to get the mean effective pressure as shown by a diagram ? 

Ans. A planimeter. No skill or mathematical 
knowledge are necessary to use this instrument. 
The readings taken from a counter on the instru- 
ment give the area of the enclosed figure. 

Qiies. What is the difference between the Indicated Horse 
Power (I. H. P.) and the Effective Horse Power (E. H. P.)? 

Ans. The effective horse power is the indicated 
horse power less the engine friction ; it is always 
less from the fact that the engine itself absorbs 
power. 

(^ues. What proportion of the indicated power does the 
engine consume ? 

Ans. With well constructed engines and every- 
thing in good working order it is probably under 
ten per cent. — but with the ordinary unbalanced 
slide valves and bad construction one-third of the 
power is wasted. 

Ques. Does a correct curve always show an economical 

engine ? 

Ans. No, because a defective leakage may be 
the same on both sides — the leakage out may balance 
the leakage in — hence it must be carefully assured 
that the piston and valves are tight. 

Ques. Does a defective diagram always indicate trouble ? 

Ans. Yes, a diagram with an incorrect curve 
necessarily and infallibly shows a wasteful engine. 



126 ENGINEERS' EXAMINATIONS. 



ELECTRICITY FOR ENGINEERS. 



The latest developments of engineering are without a 
doubt along electric lines, and, in issuing a license for a 
steam plant where there is an electrical apparatus, the Ex- 
aminer will insist upon some knowledge and practical ex- 
perience in industrial electricity — and the devices employed 
to utilize it before granting a license. 

The Electric current (so-called) is produced by a machine 
known as a Dynamo or Electric Generator ; this might be 
called the Steam Engine of Electricity as it simply transmits 
or carries along the power, produced elsewhere, to its spect- 
fied work. 

It is with the Dynamo that the Licensed engineer and \us 
assistants has primarily to do, and it is necessary that he have 
a mastery of it — in the same degree that he has of his engine. 
It is true that in the Power Stations of Electric Railways 
and other large plants that Electricians, so ranked are con- 
stantly on watch, but it is generally true tha^^ the Engineer 
has charge of the Electric apparatus. 

Next to the Dynamo the Engineer must be informed as to 
the Laws of the Transmission of the Electric Current — in 
practical language he must understand " Wiring. " 

The recent great advance in the practical developnaent of 
Electricity has come from the discovery of the Electric Motor 



QUESTIONS AND ANSWERS. 137 

— which is simply a Dynarao reversed — while the Dynamo is 
run by a belt or other mechanical means, the Motor is run 
by the electric current. A practical acquaintance with one 
answers for both the Dynamo and the Motor, although there 
are some points of difference necessary to be known. 

What is electricity is a question often asked, but w^hich 
has never yet been satisfactorily answered. It is one of the 
unexplained existences which, like latent heat, are known to 
be, but aside from their mighty and beneficial accomplish- 
nients might as w^ell remain unknown. 

How electricity is "gathered" and how it is utilized in 
some of the many machines now in use is the limit of neces- 
sary knowledge concerning it. 

It is well to remember at the beginning that magnetism is 
almost indentical with electricity, and that the way in which 
a small magnet will attract and hold a bit of iron or steel (a 
tack or nail) is the A B C of the science. Next, that iron or 
steel are the principal metals (with copper wire) with which 
ine greatest as well as the least of the electrical problems 
are worked out to a commercial and industrial success. 



Questions and Answers Relating to Electric- 
ity and Electric Machines. 

(^ues. What is an electric current ? 

Ans. It is something which seems to flow along 
Ox'- through the conducting wires ; although not 
known as to its nature it is freely called the electric 
current. 



ENGINEERS' EXA31INATI0NS. 



Ques. How many kinds of electricity are there ? 

Ans. One — although it is spoken of and treated 

as two, positive and negative. 

Ques. How are tliese designated ? 

Ans. By the plus sign + for positive and the 
negative sign — for the negative electricity. These 
signs are very useful in designating the two, 

Ques. How do these stand in relation to each other ? 

Ans. It is said that + electricity attracts — 
electricity, and that — electricity attracts + and tne 
contrary, -|- repels +, — repels — . 

Ques. How do these currents flow ? 

Ans. Positive (+) electricity and ( — ) electricity 
mean but a difference in pressure, always flowing 
from + to — as steam always flows through the 
steam pipe, engine and exhaust and never backward. 
It is impossible to generate a current of negative ( — ) 
electricity of a higher pressure than the (-J-) positive 
current, 

Ques. What is a conductor ? 

Ans. Anything that will allow the electric cur- 
rent to flow freely through it. All the lines (wires) 
carrying electricity are conductors, hence any- 
thing which allows the free passage of electricity is 
a conductor, and anything which prevents the 
passage of electricity is a non-conductor. 



QUESTIONS AND ANSWERS. 129 

Ques. Which is the most important ? 

Ans. It is just as necessary in practical work to 
have good non-conductors as it is to have good 
conductors.* 

(^iies. Name some of the conductors. 

Ans. The ground is a good conductor, vi^hich 
fact often causes great "trouble." Water is a 
conductor, and if the wires and their supports are 
wet, and if there are any conducting substances that 
will allow the passage of current to the ground, 
there is trouble again. Other conductors are silver, 
copper, iron, etc.f 

Ques. Name some non-conductors ? 

Ans. Dry air, glass, silk, asbestos, woolen and 
cotton cloth, dry paper, dry wood, oils. 

Ques. What substances are generally used for non-con 
ductors ? 

Ans. Cotton or silk, coated with paint, varnish 
or asphaltum ; the cotton and silk are the non- 
conductors, and the varnish, etc., are put over all to 
keep away the moisture. 



* All substances will allow of the passage of some electricity, but 
as there are substances that offer a very strong resistance to its pass- 
age they are generally called insulators, or simply non-conductors. 

t Silver is six times as good a conductor as iron, that is, if you take 
a silver wire and an iron wire the current will pass through the silver 
wire six times as easy as through iron. Lead will only conduct one- 
eleventh as well as silver. 



130 ENGINEERS' EXAMINATIONS. 

Ques. What is one of the most important points in keeping 
up electric machines and circuits ? 

Ans. To keep the circuits well insulated, and to 
allow no accumulation of oil and dirt around the 
machines to form a conducting substance. Lamps 
and dynamos must also be kept clean so that they 
work freely. Gas, moisture, and steam are to be 
watched for, as they all destroy the necessary insu- 
lation. 

Qiies. What is a dynamo-electric machine ? 

Ans. It is a machine driven by power, usually by 
steam or water, used to convert mechanical power 
into electrical energy. 

Ques. Describe, generally, the construction of a dyTiamo. 

Ans. There are various styles of dynamos, but 
they are all built upon similar principles. First, 
there is the magnet core, usually made of wrought 
iron ; second, around the core are wound field coils 
— the field coil is copper wire generally insulated 
with soft cotton thread and double-wound ; third, 
pole pieces, usually made of cast iron, into which 
the magnetic core is cast ; the round space between 
the pole pieces is the magnetic field — so called 
because it is there that the lines of magnetic force 
cross from one pole to the other, and where the arm- 
ature is placed ; the pole pieces are united by, fifth, 
a "yoke," which completes the magnetic current; 
this is practically an electro magnet of the horse- 
ghoe form, with the wire wound on near the poles. 



QUESTIONS AND ANSWERS. 131 

(^ues. What is the meaning of the term insulated ? 

Ans. This means removed from the sensation of 
touch, handling or feeling — rendered insensible to 
touch, 

Ques. What is the object of insulating the wire of electro 
magnets ? 

Ans. So as to form lines of travel for the mag- 
netic force. 

Ques. What would be the effect, if, through imperfect 
insulation, the wires of the magnetic coil came into contact 
at some point or other ? 

Ans. It means so much loss, and if the insula- 
tion is too imperfect the whole circuit will have to 
be abandoned or newly insulated. 

Ques. Is there any difference in the names of the poles in 
pei-manent and electro magnets ? 

Ans. In a magnet the pole into which the lines 
of force are assumed to enter is called the south 
pole ; the pole from which they are assumed to 
emerge is called the north pole — in other words the 
aorth pole is positive and the south pole negative. 

(^ues. What is a permanent magnet '? 

Ans. It is a bar of U-shaped steel which con- 
iinues magnetized for an indefinitely long time. 

Ques. What is an electro magnet ? 

Ans. It is a body of iron which becomes magne- 
tized by the electric current passing around it 



132 ENGINEERS' EXAMINATIONS. 

conducted by insulated wires — it is the opposite of a 
permanent magnet because upon stopping the 
machine the magnetic condition ceases. 

Ques. What is a switch ? 

Ans. A switch is a device used to make or break 
a circuit — the switch is so arranged that the hand 
will start it, while a powerful spring throws the 
switch open or closes it immediately. 

Ques. What is a brush ? 

Ans. This consists of a quantity of straight 
copper wires laid side by side, soldered together at 
one end and held in a suitable clamp ; two layers of 
wires are often thus united in a single brush. 

Brushes are also made of broad strips of springy 
copper, slit for a short distance, so as to touch at. 
several points. 

Ques. What is the object of slitting the brush ? 

Ans. The subdividing of the spark at the 
contact. 

Ques. What rule do you consider important relating to 
the brushes ? 

Ans. A brush should never be lifted off the 
commutator while tho dynamo is running. 

(^ues. When do the brushes cause "flashing " ? 

Ans. When they are out of position, too far 
ahead or too far back or not set directly opposite 
each other ; if the brushes do not have sufficient 
contact, a machine will frequently flash. 



QUESTIONS AND ANSWEM 133 

Ques. What is the use of the commutator ? 

Ans. The commutator or collector of a dynamo 
is used for changing the alternating currents, as 
produced in the armature, to continuous currents as 
delivered to the lines. The commutator transfers 
these currents, as they are formed, to the brushes, 
which convey them to the lines continuously in one 
direction. 

(J lies. What is the commutator ? 

Ans. In general, a cylinder made up of alternate 
sections of conducting and non-conducting substan- 
ces, running parallel with the shaft of the machine 
upon which it turns. 

Ques. What may be said about the trouble caused by the 
dynamo ? 

Ans. In the commutator and brushes will be 
found the greater part of the difficulties that the 
engineer in charge of the dynamo has to contend 
with in his electric plant. 

Ques. What is the difference between an incandescent 
hght and an arc light ? 

Ans. The incandescent* light is produced by 
passing electricity through a carbon ribbon or fila- 
ment confined in a vacuum ; an arc light is produced 
by passing electricity through two carbon pencils 
slightly separated, in open air. 



* Incandescent means white. The electricity passing between the 
points forms an " arc " or curved line. Hence the name, arc light. 



134 tlNOlN^lEnS' tlXAMmATlONS. 

Questions and Answers Relating to Gravity 
and Strength of Materials. 

Ques. What is gravity ? 

Ans. It is an unexplained force which draws 
every particle of matter toward every other particle. 
It extends to all known bodies in the universe, from 
the smallest to the greatest. 

Qiies. What is specific gravity ? 

Ans. Every substance in nature has a weight 
specific — or peculiar- — to itself. For example, pine 
wood has a certain weight and cast-iron has another 
certain weight, hence, the specific gravity of a body 
is its weigTit compared with the weight of another 
body taken as a standard. 

Ques. What is the accepted standard for all solids and 
liquids ? 

Ans. Water. 

Ques. What is the standard of comparison for all gases ? 
Ans. Air. 

Ques. When we say that the specfic gravity of iron 
(wrought) is 7. 688, what do we mean ? 

Ans. That it is seven times as heavy as water 

and Ttnnr over.* 



* The heaviest of all known substances is platinum, whose specific 
gravity is 22, water 1 ; and the lightest of all weighable bodies is 
hydrogen gas, whose specific gravity is iVlfffi common air being 1, but 
air is 818 lighter than water. Hence, by calculation, it will be found 
thut platinum is 247,000 times heavier than hydrogen, and a wide ranga 
is allowed to the various bodies which lie between these extremes. 



QUESTIONS AND ANSWERS. 135 

Ones. How may weight be defined ? What is it ? 

Ans. The weight of a body is the force it exerts 
in consequence of its gravity. We weigh a body by 
measuring the force required to hold it back, or to 
keep it from descending, hence weights are nothing 
more than measures of the force of gravity in differ- 
ent bodies. 

Ques. What is that principle which holds bodies together 
called ? 

Ans. It is the strength of cohesion ; this is the 
power residing in the minute particles of matter, 
called molecules, to cling together. 

Ques. Name four ways in which this cohesion may be 
overcome in a bar of iron or piece of timber, and the common 
names of the forces used ? 

Ans. I. The bar may be pulled asunder; resist- 
ance to this force is called tensile strength. 

2. The iron may be crushed in the direction of its 
length. This is direct thrust or compression, and 
the resistance to it is called the crushing strength. 

3. The bar may be bent or broken from the direc- 
tion of the middle or side. This is transverse strain 
or flexion, and resistance to it is called transverse 
strength. 

4. The bar may be twisted off ; this is torsion; 
resistance to it is tortional stretigth. 

Ques. Define stress and strain. 

Ans. Any bending or breaking pressure is a 
stress ; its effect on the piece is a strain ; hence the 



136 ENGINEERS' EXAMINATIONS. 

Strength of a solid piece or body is the total resist- 
ance it can oppose to strain in that direction. 

Ques. What is the Hydrometer ? 

Ans. It is an instrument constructed for the 
especial purpose of ascertaining the specific gravities 
of liquids. 

(Jues. How may the specific gravity of solids be found ? 

Ans. Advantage may be taken of the important 
fact that when a body is wholly immersed in water, 
it displaces a bulk of that liquid exactly equal to its 
own, hence the difference of its weight in water 
from that of its weight in air must be the weight ol 
an equal bulk of water. 

(Jues. What is a Salinometer ? 

Ans. It is a glass or metal instrument, by means 
of which the density of water is ascertained. In 
plain language it is a salt measure or hydrometer. 

Ques. What is the amount of salt held in solution in sea 
water? 

Ans. One thirty-third (sV). This quantity is 
called one degree, and if the watci" of a marine 
boiler tested by the instrument shows ^, it is 
expressed by saying " two degrees ", if ^, then 
three degrees, etc. 

(^ues. How are the Salinometers graduated ? 

Ans. Some into 33ds, and some into 32ds, each, 
representing about five ounces of salt to a gallon of 
water.* 



♦ Note, L e., each. 33d has 502 salt. •;,% has 1,002, -fg has 1.B02, etc 



QUESTIONS AND ANSWERS. 



137 



Qiies. 

used? 



In the use of the SaUnonieter where should care be 



Ans. They should be used on water taken from 
the boiler almost as soon as it ceases to boil, as 200° 
is the usual temperature at which these instruments 
are tested, and as the density of fluids vary accord- 
ing to their temperature. 



Ta^le of Specific Gravities. 



Iron (cast) 7.^ 

" (wrought) 7. 

Steel (soft) 7. 

" (tempered) 7. 

Lead (cast) 11. 

" (sheet) 11.^ 

Brass (cast) 8. 

" (wire drawn). . . 8. 

Copper (sheet) 8. 

" (cast) 8.( 

Gold (cast) 19. 

" (hammered). ... .19. 

" (22 carats) 1^ 

" (20 " ) 15. 

Silver (pure, cast). . . 10.^ 

' * (hammered) .... 10. 
Mercury (60°). ...... .13. 

Tin 7. 

Zinc (cast) 7. 

Bronze (gun metal) . 
Coal (Bitummous) . . . . 1. 
1. 
1. 



(Anthracite) 



207 


Charcoal. 


. . . .441 


G88 


Brick 


... 1.900 


780 


Clay 


... 1.930 


840 


Common Soil. . . . 


... 1.984 


400 


Emery 


... 4.000 


407 


Glass 


... 3.248 


384 


Grindstone 


... 2.143 


544 


Gypsum . 


.... 2.168 


767 


Lime 


... 2.720 


007 


Granite 


. ... 2.625 


238 


Marble 


... 2.708 


361 


Mica 


.... 2.800 


481 


Millstone 


. ... 2.484 


709 


Nitre 


. ... 1.900 


474 


Porcelain ........ 


. ... 2.385 


511 


Phosphorus ...... 


1.770 


580 


Pumice Stone .... 


915 


.293 


Salt 


... 2.130 


.215 


Sand 


.... 1.800 


.700 


Slate , 


. .. 2.672 


.2,:g 


Sulphur. ......... 


.... 2.083 


.436 






.640 







1S8 £ifOWE£]liS' EXAMINATIONS. 



HORSE POWER (H. P.) 



The capacity of work of a steam engine, a steam boiler, 
or of a whole steam plant is reckoned in horse power. The 
abbreviation of the term is H. P. 

A horse power is 33,000 foot-pounds, or in other words, 
33,000 pounds lifted 1 foot high in 1 minute, or 550 pounds 
lifted 1 foot in 1 second of time, hence 

A foot-pound is one pound moved upward one foot. 
Example, work done by hfting 30 pounds through a height 
of 50 feet = 1,500 foot-pounds. 

While, by means of the Indicator, the horse power of the 
steam engine can be determined to a nicety, the horse power 
of the steam boiler is almost an unknown quantity ; it has 
been agreed upon, however, to consider the evaporation of 
30 lbs. of water in 1 hour to be the standard of efficiency.* 

(^ues. What are the three kinds of horse power spoken 
and written about, which engineers should learn to dis- 
tinguish ? 

Ans. Nominal, Indicated and Effective. 



* The several tests made on the boilers used in the recent Chicago 
Exposition tend to prove that there has been no improvement in the 
maximum efficiency of boilers since 1876. But boilers are now made 
which carry high pressure as safely as were the pressures of 1876 by 
the boilers then made. 



QtJiESTtONS AND AJ^STTERS. V6Q 

Ques. What is the difference between these ? 

Ans. The nominal (N. H. P.) is only used as a 
general statement describing the dimensions of a 
steam engine for convenience of makers and pur- 
chasers of steam engine. 2d, the indicated (I. H. P.) 
is the "calculated" work done within the cylinder. 
3d, the effective (E. H. P.) is the vi^ork an engine 
can do after deducting the amount required to drive 
the engine when it is running unloaded. The letters 
in brackets show the abbreviations of the terms. 

Ques. How is the horse power of the boiler best deter- 
mined V * 

Ans. The only sure method is by the actual 
measurement of the water evaporated. 

Ques. In getting this measurement what precautions 
should be taken '? 

Ans. Even when the amount of water intro- 
duced and the quantities passed off from the boiler 
are accurately known, there yet remains a doubt as 
to how much has been actually evaporated, and how 
much may have passed off in priming, unless the 
trial has been conducted with the boiler open to the 
atmosphere. To have the boiler thus open appears 
to be the only condition under which accuracy can 
be insured, unless a suitable apparatus can be pro- 
vided for accurately measuring the weight and tem- 
perature of all thi steam and water given off, when 
the boiler is working above atmospheric pressure. 

* For the rule for calculating tbe horse power of the Steam 
Engine, see pages 79 and 80. 



140 ENGINEERS' EXAMINATIONS. 

Ques. Can any boiler be said to be free from priming ? 

Ans. There are very few boilers which do not 
prime more or less, and the quantity of water passed 
off in this way is quite considerable. 

Qnes. In view of these facts, can there be any accurate 
results obtained in boiler tests ? 

Ans. Unless the amount of water passed over 
with the steam by priming or foaming, when work- 
ing under pressure, can be accurately ascertained, 
the evaporative results are not to be relied upon, 
however careful in other respects the trial may have 
been conducted. 

Ques. Is the intensity of boiling itself constant ? 

Ans. It is not, as the heat is ever varying during 
the intervals between firing, and the difference in 
height is thus dependant and changeable. 

(^ues. What is the ordinary shop rule for estimating the 
horse power of the horizontal tubular boiler V 

Ans. It is customary to consider fifteen square 
feet when exposed to the heat as being a horse 
power, and it is figured by the following : 

Rule for Estimating the Horse Power of Horizon- 
tal Tubular Steam Boilers. 

Find the square feet of heating surface of the shell, heads 
and tubes, and divide by 15 : the answer is the nominal horse 
power. 



ICE MAKING AND REFRIGERATION. 141 



ICE MAKING AND REFRIGERATION. 



The connection between steam engineering and refrigera- 
tion is equally intimate as that which exists betw^een engi- 
neering and electricity. 

Both refrigeration and electricity in their practical appli- 
cation to the service of mankind demand the highest 
engineering skill, and it goes without saying that the engineer 
who is an expert in either of these widening lines of progress 
will receive comparatively the highest pecuniary return for 
his service. 

That buildings will be soon cooled and ventilated in an 
artificial manner is assured by the high efficiency now 
attained by mechanical refrigerating machines ; some modi- 
fication of the methods now employed in cold storage houses 
will be adopted for buildings, and as steam will be the 
actuating force, engineers must necessarily be employed in 
the care and operation of the machinery. This makes it 
desirable that the engineer should become as thoroughly 
posted as possible, regarding the principles and operation of 
the various mechanical refrigerating systems now in use, as 
well as those which will hereafter be developed, and he will 
find it greatly to his advantage to do so. 

The principles governing artificial refrigeration are simple 
and are becoming familiar to many engineers, yet many 



142 ICE MAKING AND REFRIGERATION. 

engineers understand the practical workings of the machines 
better than they do the principles upon which they operate — ■ 
in view of the large future opening to this comparatively 
new industry it were well to unite the two. 

A few easy definitions at the introduction of the subject 
may make the path of instruction plainer. 

A refrigerant is anything which abates the sensation of 
heat, or cools. 

To refrigerate is to cool ; to make cold ; to allay the heat 
of — 

A refrigerating -machine is a machine for the artificial 
production of cold. 

Refrigeration is specifically the operation of cooling various 
substances by artificial processes, and 

Chemical refrigeration is effected by the use of freezing 
mixtures, which have the property of producing a sufficient 
degree of cold to freeze liquids. 

Mechanical Refrigeration, in its strictest sense, is the con- 
version of heat into work by the expansion of a volume of 
gas or vapor, which performs work during the act of expan- 
sion ; in a broader sense, it is a process of refrigeration in 
which the cycle of heat changes is only partly ..produced by 
mechanical action, the mechanical part of the process being 
wholly confined to compressing tlie gas or vapor while 
liquifying it under the action of cold and pressure. 

Every refrigerating apparatus consists of three parts, viz. : 
1. The power (an engine), and gas (ammonia) pumps which 
compress the gas to a liquifying pressure. 



QUESTIONS AND ANSWERS. 143 

2. A condenser in which the gas is cooled and changed to 
a liquid. 

3. A system of evaporating coils, in which the liquid 
ammonia is expanded into a gaseous state and thus cools the 
surrounding si^ace by the absorption of heat. 

The refrigerating agent better than any known substance 
which has proved most advantageous is ammonia. This 
chemical boils at 40° below zero — as water boils at 212° above 
zero — thus assuring a low temperature without resorting to 
very low pressures. 



Questions and Answers Relating to Refrig- 
eration. 

Ques. What is anhydrous ammonia ? 

Ans. The word anhydrous means "free from 
water ": ammonia unmixed with water is sometimes 
called dry ammonia. 

Qiies. What are the advantages of ammonia over other 
fluids for refrigeration ? 

Ans. Its great stability, its non-inflamibility and 
non-explosiveness ; it does not have the slightest 
effect on iron and steel, even when mixed with water, 
so that the machinery and piping which convey and 
circulate it are never in the least degree corroded, 

Qiies. What is the standard of cold production ? 

Ans. It is the weight of the gas circulated through 
the system and not the volume of gas. 



144 ENGINEERS' EXAMINATIONS. 

Qiies. How much cold can be produced from a pound of 
coal? 

Ans. Numerous tests have shown that with a 
fairly constructed refrigerating machine a melting 
capacity equal to that of 16 to 48 lbs. of ice can be 
obtained from a lb. of coal.* 

Ques. What is the Brhie system of refrigeration ? 

Ans. In the Brine system one or more tanks of 
salt water are used, in which the evaporating coils 
are submerged, and the liquid ammonia, allowed to 
expand within the coils, assumes its original gaseous 
condition and in doing so absorbs the heat from the 
surrounding brine, reducing it to any reouired tem- 
perature. 

(^ues. In ice making how is the brine tank arranged ? 

Ans. It is arranged to receive galvanized sheet 
iron cans containing fresh water, which remain in 
the brine until their contents are frozen into solid 
blocks of ice. 

Ques. What is the direct expansion system ? 

Ans. In the direct expansion system the ammonia 
expands directly in coils placed in the rooms to be 
cooled. 

(Jues. Which system (brine or direct expansion) is mostly 
used, and why ? 

Ans. The brine system, because the brine tanks 
afford a considerable reservoir of cold which may be 



* The wide difference given is shown hy the tests and it will b^ 
found that the capacity varies with the conditions. 



QdESTIONS AND ANSWERS. 145 



drawn upon in an emergency; another strong reason 
is that there is less risk of loss in the cooling rooms 
from escaped ammonia from leaking pipes ; still 
another reason for preferring the brine system is 
because the whole system of the ammonia gas 
circulation is confined to one room or department 
and directly under the control of the engineer. 

Ques. In the brine system how is the brine circulated ? 
Describe the process. 

Ans. It is accomplished by a special pump 
described as the brine circulating pump, which 
forces it through the pipes arranged in the rooms to 
be cooled, from which it returns to the tank to be 
re-cooled and continually used over again, through 
an endless round of cooling and warming. 

Ques. Is the brine circulation quite independent of the gas 
circulation ? 

Ans. Yes, the only spot they come in contact is in 
the brine tank ; here the cold ammonia gas extracts 
the heat from the brine as it flows through the tank; 
the two circulation systems do not come in nearer 
contact than that. 

Ques. How is the cooling effected in the direct expansion 

system ? 

Ans. In the direct expansion system the ammonia 
expands directly in coils placed in the rooms to be 
cooled, the pipes being stronger but in other respects 
similar to those used in the brine circulation ; in 
this system the brine pump is omitted. 



146 ENGINEERS' EXAMINATIONS. 

Ques. What is the difference between a submerged con- 
denser and an open air condenser ? 

Ans. In one plan the system of pipes is sunk in 
a tank containing water and in the other the pipes 
are exposed to the air and water sprinkled over 
them. 

Ques. In either plan or method what is the common 
result ? 

Ans. The water extracts the heat from the pipes, 
being under the requisite pressure the ammonia is 
cooled to the temperature of the condensing water, 
and becoming liquified, is ready for use. 

Ques. What other principal system of refrigeration is in 
use ? Describe it. 

Ans. The absorption system. This consists in 
a different arrangement of i, the power, 2, the con- 
denser, and 3, the evaporating coils, as mentioned 
on page 142.* 

Ques. What are the parts of the absorption system spec- 
ially called ? 

Ans. I. The Generator. 2. The Ammonia Pump. 
3. The Absorber. 4. The Condensing Tank. 5. 
Weak Liquor Tank. 6, The Equalizer, 7. The 
Freezing Tank. 8. The Cooling Tank. 9. Receiver 
for Ammonia. 



* These are mentioned on page 142 as essential to all systeroa pt 
refrigeration. 



QUESTIONS AND ANSWERS. 147 



Ones. What refrigerant is mostly usetl in the absorption 
system ? 

Ans. Ammonia largely reduced and mixed with 
water so that it is 26 per cent, strong — called prop- 
erly, aqua-ammonia. 

(jues. Upon what chemical law is the absorption system 
based ? 

Ans. Upon that which allows ammonia to boil 
into gas at 40 degrees below zero, while water is 
unaffected until 2 1 2 degrees is reached ; the ammonia 
and water are thereby capable of being separated 
and thus made to perform continuous work. 

Qiies. What is the expansion valv«e ? 

Ans. It is that which controls the supply of 
ammonia to the evaporating coils. 

Qiies. What advantage is to be gained by the use of the 
device called "the agitator " ? 

Ans. Its use is to secure uniform freezing, which 
is accomplished by continually circulating and agi- 
tating the bath — this is sometimes done by the use 
of a centrifugal pump, which draws the brine from 
one end at the bottom and discharging in the other 
end at the top. 

(|ues. What is the cycle or circle of the ammonia in its 
two forms through its round of use and re-use ? 

Ans. I. Compression. 2. Condensation. 3 Ex- 
pansion. In qrder to render the operation continu- 



148 ENGINEERS' EXAMINATIONS. 

ous these three are connected together, the gas 
passing through the system in the order named. 

Ques. To what extent is the ammonia compressed ? 

Ans. From 125 to 175 lbs. per square inch, 
depending upon the temperature of the condensing 
water used, either mechanically or otherwise, in 
order to prepare it for the second operation-express- 
ed more plainly, "heat is squeezed out of the gas. 

Qiies. How about the condensation ? 

Ans. The heat developed or "squeezed out "in 
the compression is withdrawn from the compressed 
gas by forcing it through coils of pipe while they are 
in contact with cold water — the heat being trans- 
ferred to the water surrounding the coils.* 

Ques. Of what does the expansion side consist and what 
is its operation ? 

Ans. The expansion side generally consists of 
coils of pipe, in which the gas re-expands and per- 
forms the refrigerating work ; through these pipes 
the ammonia gas is drawn by the pumps at a press- 
ure varying from 10 to 30 lbs. above that of the 
atmosphere. 

Ques. Where do the " parts " meet ? 

Ans. The liquified gas is allowed to flow to a 
stop-cock having a minute opening which separates 
the compression from the expansion sides. 

* When this point is reached the gas is ready to assume the liquid 
condition, and in so doing, is ready to give off additiooal heat totUfi 
ewrouading water. 



QUESl'TONS AND AN$Wi]RS. 149 



Ques. What are air machines ? 

Ans. Machines that use air instead of ammonia; 
cold can be generated by the expansion of air ; air 
becomes heated under compression and will cool 
down again during compression. Air machines are 
generally used on ship-board where machines of 
comparatively small capacities are needed. 

Ques. What are the objections to air machines ? 

Ans. Their large coal consumption, which is 
eight to ten times that of good ammonia-compress- 
ion machines— besides this the compressing-pumps 
are very large, the friction to operate them is great 
and the loss by leakage around the piston becomes 
considerable in course of time. 

Ques. What is a double-acting compressor ? 
Ans. One which handles the gas on Doth the 
upward and downward stroke. 

Ques. What are its advantages ? 

Ans. The friction will be the same for all the 
working parts, while double the work is being 
effected. 

Ques. What is the greatest trouble to be overcome in 

refrigerating machinery 'i 

Ans. Leakage. 

Ques. What should be one of the first rules as to the 
machinery and appliances ? 

Ans. They should be kept clean and in good 
order ; means should be provided for cleaning the 
entire distilling system by steam. 



160 iiiSAt A^D WoM^ 



HEAT AND WORK. 



Without heat there would be no steam engine nor steair 
boiler, neither engineer or fireman. 

The services of the engineer are chiefly devoted to chang- 
ing heat into work ; the heat which is carried to the engine 
in the steam is either transformed into useful work, or it 
passes away to waste in various ways, and the sum of the 
heat usefully employed plus the heat which is wasted always 
equals exactly the heat which was applied. ' 

This is owing to a fundamental principle in nature that, 
just as matter can neither be created nor destroyed, though 
it may be made to assume different forms, visible or invisible, 
so energy, whether heat energy or any other, cannot be 
destroyed. It may take a variety of different forms, but the 
sum total of the energy remains the same. This principle is 
called the principle of the ' ' conservation of energy. " 

The temperature of a body indicates how hot or how cold 
the body is. 

We must not fail, however, to distinguish the temperature 
of a body from the quantity of lieat in a body. Thus, if a 
cup of water be dipped out of a pailful of water, the temper- 
ature of the water is the same throughout, but the quantity of 
heat varies as the weight of water in each vesseL 



BEAT AND WORK. 151 

Before quantities of heat can be measured we must have a 
unit of heat, just as we require a unit of length. Namely ; 
the inch or foot in order to measure distance, or the pound 
or ton in order to measure weight. 

The unit of heat is the amount of heat necessary to raise 
the temperature of one pound of water one degree Fahren- 
heit when at a normal temperature. 

Heat is transferable from one body to another, that is, one 
body can heat another by becoming less hot itself ; thus, the 
furnace heat is transferred to the boiler plates, thence to the 
water and steam, and finally to the piston, in the driving of 
which heat is changed into work. 

The natural condition of heat is a condition of energy, that 
is of a condition to effect changes — of coal into gas, of water 
into steam — and steam into work. 

Ques. What is the mechanical equivalent of heat ? 

Ans. The amount of heat necessary to raise i 
lb, water from or near its freezing point (32°) one 
degree, is equivalent to the mechanical power which 
will raise 772 lbs. through a height of one foot. 

Ques. How can we express units of heat as units of work? 
Ans. Multiply the units of heat by 772. 

Ques. How does this question of heat and work affect the 
engineer ? 

Ans. The whole business of the engineer is the 
superintendence of machines by means of which the 
conversion of heat may be carried out. 



152 HEAT AND WORK. 

Ques. What is a thermometer fcH* and how does it act ? 

Ans. Thermometers are used to indicate tern* 
perature, and they do so by the rise and fall of a 
little column of mercury enclosed in a tube of very 
fine bore, and having a small bulb at the bottom 
containing a store of mercury. 

Qlies. How does this show change of heat or temperature? 

Ans. If the thermometer be warmed by any 
means, the mercury expands and tends to occupy a 
larger volume, and the column therefore rises in the 
stem of the tube ; or, if the thermometer be cooled, 
the mercury will contract or diminish in volume, 
and the column will shorten or fall. A graduated 
numbered scale is affixed and the smallest change in 
temperature shown by the movement of the surface 
of the column is thus very easily detected. 

Ques. How is the thermometer scale divided or grad- 
uated 1 

Ans. The instrument is placed in melting ice, 
and the point to which the mercury falls is marked 
the freezing point. It is then put in boiling water 
exposed to the air and the point to which the mer- 
cury column rises is marked the boiling point. The 
distance between these two points on the most com- 
monly used thermometer, the Fahrenheit, is divided 
into 1 80 equal parts or degrees. 

On the Centigrade thermometer the distance be- 
tween these two marks is divided into 100 equal 
spaces or degrees — the word Centigrade is derived 



HEAT AifD WORK.. 



15B 



from the two words meaning a grading by the hun- 
dred. 

In the Reaumur scale, the same distance is divided 
into So degrees. 

Qiies. What is the position of zero on these scales ? 

Ans. The last two make the freezing point zero, 
while the Fahrenheit makes the freezing point 32° 
and thus the zero is i8o°-|-32°, or 212° below boiling 
point, and temperatures are measured from zero up 
and down the scale. 

(^iies. Wliat is meant by the term "energy " ? 

Ans. It may be defined as the power of doing 
work. When heat is applied to water it confers 
upon the steam which is produced the power of 
doing work, such as driving the piston from one end 
of the cylinder to the other, against a resistance. 

Ques. What is specific heat ? 

Ans. It is the heat required to raise the temper- 
ature of a substance one degree, as compared with 
the heat necessary to raise the temperature of an 
equal weight of water one degree. 

The specific heat of bodies varies very considerably, as will be seen 
from the following table : 

Table of Specific Heat. 
Water 



Cast Iron . 






= i.UUU 

=0.130 


Steel 






. =0.118 


Wrought Iron 






=0.113 


Copper 






=0.100 


Bismuth . 


, 




=0.031 


Lead 


, 




=0.031 


Mercury . 


» • 




=0.033 


Coal 


» 




=0.241 



154 Mt}AStJttt:S ANi) WMOffM. 



MEASURES AND WEIGHTS. 



A large proportion of time is taken up in counting, in 
measuring and in weighing, and an engineer's success in the 
path of advancement is largely influenced by his readiness in 
these. 

To avoid disputes there needs to be a certain well agreed 
upon standard, both of weights and measures, by which 
all will agree to be governed. 

This agreed standard for each operation is called the unit. 

(Jues. What is the unit or measure of time ? 

Ans. A minute. 

(Jues. What is the unit of arithmetical calculations ? 

Ans. The figure (i) one. 
Ques. What is the unit of pressure ? 

Ans. The pressure of the atmosphere at the level 
of the sea. 147% lbs. to the square inch. 

Ques. What is the unit of work ? 

Ans. The foot-pound, which is the force required 
to lift one pound one foot high. 33,000 of these 
make one horse-power when executed in the unit of 
time (one minute). 

Ques. What is the unit of heat ? 

Ans. It is the heat required to raise one pound 
of water one degree — or say, one pound of water 
from 32° to 33°. 



STEAM HEATING AND VENTILATION. 155 



STEAM HEATING AND VENTILATION. 



No small proportion of engineers' positions are retained, 
after being secured, by a practical familiarity with the care 
and management of the heating and ventilating apparatus , 
it is true that nearly always this apparatus is furnished, as 
to plan and detail, by the architect, yet the engineer must 
operate it to the satisfaction of the owner of the steam plant, 
or lose his situation 

Hence it follow? thnt no engineer v/ill be granted a license 
to run a steam plant, wnere there is an extensive system o£ 
heating, unless he shows by his answers that he is capable of 
its management and ujiderstands, somewhat, the principles 
upon which it acts, 

A system of heating and ventilation should, in the first 
place be simple, so that the average engineer shall be compe- 
tent to operate it. It should be of sufficient capacity to do 
the heating required for all the space, and it should be safe, 
durable and economical. 

In planning and in the management of the apparatus, both 
t'ae heating and. ventilation should be considered as one — they 
are inseparable and together form a complete whole; the 
apparatus shonlcl warm the air in an enclosed space to a 
temperature conducive to comfort and health, and supply a 
fidlunie of oAr sufficient to maintain a sanitary standard of 
pvrifif; both coaditions — heatina: and ventilation — must b*; 



156 ENGINEERS'' EXAMINATIONS. 

controllable and constant, with the air deliveries so made tliat 
no complaint can be found with the engineer-in-cliarge. 

In heating and ventilating the natural laws which govern 
must be regarded, otherwise all applications will be experi- 
mental, thus: 

1. Air occupies space the same as solids and liquids, but 
because it is invisible it is not so regarded. 

2. Cold air falls because of its density and heated air 
rises because of its rarity. 

3. A given volume of air occupies a given space ; a like 
volume cannot occupy the same space at the same time. 

4. A volume of air can be delivered into a room only 
equal to the quantity displaced therefrom ; when a space is 
full it can hold no more. 

Ventilation is a substitution of fresh air for foul ; it should 
be a gradual, constant and complete changing of the air in a 
room or structure. 

The piping of a mill or factory or workshop was, compara- 
tively, a few years ago, an easy task. To-day high buildings, 
v/ith hundreds of business offices, government buildings with 
elaborate equipment and furniture, art institutes and 
museums with treasures and relics, mansions and cottages, 
are being warmed by special systems studied out by the 
mechanical engineer and master steam-fitter. 

The systems are becoming intricate ; they require drawings, 
planning, accurate measurements and calculations on areas 
and capacities, mechanical knowledge of steam and water, of 
pipes, furnaces, boilers, valves, fittings and those other 
adjuncts which have become necessary in the extensive iise 



QUESTIONS AND ANSWERS. 15"? 

of steam and hot water. In short, there is a great deal to be 
learned concerning present methods, and a great deal more 
to be learned la the future, as experience, invention and 
improvement will show. 

It is, therefore, time for this branch of business — steam 
and hot water heating — to be recognized as one worthy of 
attention, investigation and study. 



Questions and Answers Relating to Heating 
and Ventilation, 



(Jues. What is a very important princii)le to be observed 
in arranging a system of piping ? 

Ans. They should be so designed that there is a 
gradual slant from feed to return, with no air or 
water " pockets " and nothing to be in the way of a 
thorough circulation. 

(Jues. How should the fire surface of a boiler be propor- 
tioned to the quantity of pipe to be heated ? 

Ans. The extent of surface which a boiler should 
expose to the fire should be proportional to the 
quantity of pipe to be heated, and a small apparatus 
should have more surface of boiler in proportion to 
length of pipe than a larger one, as the fire is less 
intense and burns to less advantage in a small fur- 
nace than in a large one. It is more economical to 



158 ENGINEERS' EXAMINATIONS. 

work with larger surface of boiler at moderate heat 
than to keep the boiler at its maximum temperature. 



i 



Ques. In taking charge of a new plant, what is the first 
thing to be done by the engineer ? S 

Ans. To ascertain the exact course, size and 
operation of the steam, water, drain and other pipes. 

Ques. Why is it necessary to do this so soon ? 

Ans, Because the boilers cannot be supplied 
with water even, nor blown off without the pipes 
being in order, nor steam taken to the engine nor 
distributed in a heating system without proper con- 
nections. Besides, it is well to do the most difficult 
thing first — the piping, being largely out of sight, is 
most difficult to inspect — more so than the engine, 
boilers or pumps. 

Ques. Name some of the essentials to an efficient system 
of piping ? 

Ans. Pipes and valves should be of sufficient size 
to carry the full pressure of the boiler to the engine; 
elbows with a long turn are best, and T's are to be 
avoided, if possible. Pipes of proper size and easy 
bends are essential to economy. 

(^ues. What other matter relating to the piping is essential 
to economy ? 

Ans. The covering of all pipes by some good 
non-conducting substance, as condensation in the 
pipes when uncovered or partly covered increases 
greatly the cylinder condensation. This covering i,s 



QUESTIONS AND ANSWERS. 159 



as important in warm as in cold weather, as steam 
So to loo lbs. pressure has a temperature of 325 to 
342 degrees of heat. 

Ques. What is well to be known by an engineer relating 
to steam fitting and piping ? 

Ans. It is almost a necessity to know the names 
and uses of pipe fitter's tools, to be familiar with the 
different fittings and styles of valves, sizes, ete. 

(Jues. What are some of the fittings ? Name a few of 
them. 

Ans. Gaskets, nipples, steam and water unions, 
couplings, ells, lock nuts, off-setts, coils, radiators, 
steam traps, headers. 

Ques. What is the very best non-conductor of heat ? 

Ans. Confined air — hence the best composition 
for steam pipes is that which has the largest quan- 
tity of confined air mixed with the material of which 
it is composed. 

Ques. In pipe covering what two dangers must be guarded 
against ? 

AilS. The danger of fire, and second, that there 
are no currents of air formed between the pipe and 
the covering. 

(^ues. What is the latest idea in regard to ventilation ? 

Ans. That the best results are only to be had by 
a mechanical system, extracting the air and replac- 
ing it by fresh supplies — hence the increasing use of 
exhaust fans and blowers driven by various motors. 



160 THE SMOKE PROBLEM. 



THE SMOKE PROBLEM. 



Much vexatiovis litigation has been caused by the " smoke 
nuisance ", so denominated in the ordinances passed by rafoiy 
cities ; there has been a hvely controversy between the offi- 
cials and steam-visers as to, first, the possibility and, second, 
the practicability of preventing smoke from issuing from the 
tops of the chimneys of steam plants. Many proprietors 
have been called to the bar of justice and fined for the 
offence, and not a few engineers have been threatened with 
arrest ; at times both engineers and owners have been sum- 
moned to plead guilty or not guilty to the crime of smoke 
production. 

That smoke can be absolutely prevented is proved by the 
operations of gas works, which yearly converts mto gas, 
coke, tar, etc., millions of tons of bituminous coal without 
smoke. 

The smokeless combustion of powdered coal, which has 
recently become an important fact in Europe, is greatly 
facilitated by the adoption of a new automatic mechanism 
and other arrangements. The fuel, instead of being intro- 
duced in the ordinary manner, is first ground to a powder, 
and, in place of the ordinary boiler fire-box, there is a com- 
bustion chamber in the form of a closed furnace lined with 
firebrick, and having an injector similar in construction to 
those used in oil burning furnaces. This chamber has two 
openings, one on the centre line and in the place of the usual 



THE SMOKE PROBLEM. 161 

furnace fire dooi* and the other on the opposite side The 
orifice of the nozzle is placed in the latter aperture and 
throws a constant stream of fuel into the chamber, the 
nozzle being so located that it scatters the powder throughout 
the whole space of the firebox ; when the powder is once 
ignited, which is very readily done by first raising the lining 
to a high temperature by an open fire, the combustion con- 
tinues in an intense and regular manner under the action of 
the current of air which carries it in. This current is regu- 
lated by the amount of powder required for the production of 
the heat led off to the boiler and the evaporation of the 
weight of steam demanded. 

It may thus be seen that the question is not one of possi- 
bility but of practicability or economy ; it being allowed that 
smoke prevention cannot be economically effected, then the 



English, towns are more troubled by the smoke nuisance than any 
of those of our own country. The absolute abatement of the smoke 
being economically impossible, the cities have adopted ordinances to 
control and minainiize the nuisance. Thus Manchester, for example, 
has a city law which permits of the continuous emission of black 
smoke from any factory for one minute each half hour. Oldham 
allows nine minutes per hour. St. Helens, Newcastle-on-Tyne and 
Leeds, five minutes. At Birmingham the inspectors watch the chim- 
ney for an hour ; they report the way in which the smoke is emitted, 
whether continuous or at intervals. For a first offense, or where a 
long time has elapsed between offenses, letters of caution are sent out. 
Shetfleld allows six minutes in the hour, but where there are not more 
than three steam boilers and no furnaces, four minutes in the hour 
only. At Stoke-on-Trent if black smoke is emitted for a longer period 
than fifteen minutes, proceedings are taken. Bolton allows two and a 
half minutes in the half hour. In this connection it may be of inter- 
est to state that the Manchester Association has caused 1827 half- 
hourly observations to be made of various chimneys of the members, 
and the result of these observations showed that black smoke issued 
for 3224 minutes, an average cf one minute forty-six seconds per half 
hour. 



163 THE SMOKE PROBLEM. 

problem is as to a medium effect. Attention is called to the 
foot note regarding the practice obtained in England in 
dealing with the question. 

"Human nature has not," said recently a distinguishe** 
lecturer, "is not, nor will it ever, be able to dole out the 
exact equivalent of air necessary for the complete consump- 
tion of each fresh charge of coals on the furnace grate." 
One of the reasons given was, ' ' that coals differed so much 
in the quantity of their constituents as to make the above 
impossible. " 

In an investigation made by the lecturer, data was collec- 
ted of the number of tons of coal consumed in a given time 
by thirteen puddling furnaces, and also of the color of the 
smoke em'".ted from the same. About 30,000 cubic feet of 
smoke gases were emitted every seventy seconds, of which 
the speaker declared that, "he was willing to forfeit any 
reasonable sum of money, if any one could prove that there 
was more than one part by weight of unburnt fuel in 2,680 
parts, owing to rarefaction and the smoke on the average 
being only of a ligMt brown color. " 

One point niade is not without its pertinence in the present 
crusade against the smoke nuisance, and it is given as stated 
regarding some unreasonable prosecutions made of offenders : 
" If people more generally knew what the composition of 
smoke was, manufacturers would not in many cases be per- 
secuted and prosecuted as at present, and authorities would 
exercise their discretionary powers in a more sensible and 
lenient manner. " It need hardly be said that in very many 
instances of offense this criticism is not without its weight. 



QUESTIONS AND ANSWERS. 163 



Questions and Answers Relating to the 
Prevention of Smoke. 

Qnes. 'V\1iat is the first requisite in the solution of the 
smoke problem ? 

Ans. Its formation should be prevented at the 
start, as the after-combustion or burning of smoke is 
almost impossible and quite the reverse of econom- 
ical. 

Ques. Give the generally accepted practice in prevention 
of smoke. 

Ans. A high furnace temperature is most essen- 
tial and this is best secured by a good draft; second, 
ample space in the furnace or combustion chamber 
for the mixture of the products of combustion 
(gases), mixed with, third, a due proportion of air ; 
this must be supplied in some common sense manner, 
either through perforations in the furnace door or 
through minute openings in the bridge or side walls. 

^ues. Where must the air be otherwise supplied ? 
Ans. Through the grate bars. 

Ques. What proportion of air space should there be 
between the bars ? 

Ans. Generally speaking, 50 per cent., although 
this amount may be increased for large size, hard 
and lump, bituminous coal ; for pea or nut coal the 
distance between the bars must be less. 



164 ENGIlsrEERS' EXAMINATIONS. 

Ques. What are some of the principal difficulties in the 
way of smoke prevention ? 

Ans. The worst trouble comes from uneven 
chimney draft, and again the varying qualities of 
coal which require different quantities of air-admix- 
ture. 

Qnes. Is there any difference made in the quantity of 
smoke by having too much or too little air ? 

Ans. Yes, either too much or too little air causes 
imperfect combustion — hence the smoke. 

Ques. If the exact quantity of air needed was supplied to 
the furnace, would there be any smoke ? 

Ans. Not any to be observed. It may be said 
thus — with no air absolutely no combustion ; with 
right quantity — then perfect combustion ; with too 
much or too little then — smoke. 



Computations usually made of stack capacity assume the chim- 
ney gases to be of the same specific gravity as air. This is not true, 
as when combustion is complete the gases are really a mixture of 
carbonic acid gas, nitrogen and steam ; the proportions varying with 
different coals. As these require different amounts of air, the vary- 
ing weights of the gases of combusiion cause a difference in the draft 
power of the same chimney. It is rare that just the proper amount of 
air is admitted, and there is a loss when the amount is too little or too 
great. YevY often there is a surplus of air. reaching sometimes as 
high as 100 per cent. 



ARITHMETICAL SIGNS. 165 



ARITHMETICAL SIGNS. 



There are various characters or marks used in arithmetical 
computations, to denote several of the operations and propo- 
sitions, the chief of which are as follows : 

= Equal to. The sign of equality ; as 100 cents=$l, signi- 
fies that 100 cents are equal to one dollar. 

— Minus, or Less. The sign of subtraction ; as 8— 2=6 ; 
that is, 8, less 2, is equal to 6. 

-{- Plus, or More. The sign of addition ; as 44-5=9 ; that is, 
4, added to 5, is equal to 9. 

X Multiplied by. The sign of multiplication ; as 6x6=36 ; 
that is, 6, multiphed by 6, is equal to 36. 

~ Divided by. The sign of division ; as 12 -=-3=4 ; that is, 

12, divided by 3, is equal to 4. 

: is to ) 

. ( The signs of proportion ;as2:4::8:16; that is, 
: : so IS > ° jr- r- ' > 

, i as 2 is to 4, so is 8 to 16. 

7 — 2-j-5=10. Shows that the difference between 7 and 2, 
added to 5, is equal to 10. 

^ added to a number, signifies that the number is to be 
squared ; thus : 6-, means that 6 is to be multiplied by 6. 

^ added to a number, signifies that the number is to be 
cubed; thus : 53 = 5x5x5=125. The index, or poiver, 
is the number of times a number is to be multiplied by 
itself, and is shown by a small figure placed at the right 
of the number to be raised, and a little elevated. 
The bar signifies that all the numbers under it are to be 
taken together ; as 7+4-3=8 ; or, 5x6+4=50. The 
parenthesis ( ) is sometimes used in place of the bai*. 



166 SVMMAnr OF ABtTHMETtC. 



SUMMARY OF ARITHMETIC. 



The following abridgment of several of the rules of arith- 
metic, often referred to in elementary books on mechanical 
science, are here inserted for the convenience of reference. 
These rules and examples are given merely to refresh the 
memory, it being taken for granted that the reader has 
already acquainted himself w^ith the principles of common 
arithmetic. They vs^ill, ho we er, be found serviceable, both 
as a convenience of reference, and to give some insight to the 
subjects on which they treat. 

DECIMAL FRACTIONS. 
A decimal fraction derives its name from the Latin decern, 
"ten," which denotes the nature of its numbers, representing 
the parts of an integral quantity, divided into a tenfold pro- 
portion. It has for its denominator a unit, or whole thing, 
as a gallon, a pound, a yard, &c., and is supposed to be 
divided into ten equal parts, called tenths ; those tenths into 
ten equal parts, called hundredths, and so on, without end. 

The denominator of a decimal being always known to con- 
sist of a unit, with as many ciphers annexed as the numera- 
tor has places, is never expressed, being understood to be 10, 
100, 1000, &c., according as the numerator consists of 1, 2, 3, 
or more figures. Thus : -f^ -f^^ iWo <^c., the numerators 
only are written with a dot or comma before them, thus -2 
24 -125. 



SUMMARY OF ARITHMETIC. 167 

The use of the dot (*) is to separate the decimal from the 
whole numbers. 

The first figure on the right of the decimal point is in the 

place of tenths, the second in the place of hundredths, the 

third in the place of thousandths, &c., always decreasing 

from the left towards the right in a tenfold ratio, as in the 

following 

Table. 



§ "^ S "S .•'So 

■■■ "^ ^ M S g ^ 



o 










^ 


0) 








H 










p 








o 


^ 








^ 


H 


n3 

a 


^. 






O 


a> 














w 




O 





-s s s ^ ^. -^ 



r, I'mwj <»'^l3 a^i5i' I'li'^ o^w^IJ 1* S 

Ascending. Descending 

A cipher placed on the left hand of a decimal decreases its 
value in a tenfold ratio by removing it farther from the 
decimal point. But annexing a cipher to any decimal does 
not alter its value at all. Thus 0-4 is ten times the value of 
0-04, and a hundred times 0-004. But 0-7=0-70=0-700= 
0*7000, &c., as above remarked. 

0*2 is read two-tenths. 

0-25 " " twenty-five hundredths. 

0"375 " " three hundred and seventy-five thousandths. 

0'1876 " " one thousand eight hundred and seventy -six 
ten thousandths, and so on. 

Mixed numbers consist of a whole number and a decimal ; 
as 4-25 and 3-875. 



168 



8t7MMABr OF ARITHMETIC. 



Addition of Decimals. 

Rule. — Arrange the numbers so that the decimal points 
shall be directly OA'er each other, and then add as in whole 
numbers, and place the decimal point directly below all the 

other points. 



FRACTIONS. 

^^ is the same as 

,30.. 







7 
84 

5 
480 
685 



5 

07 
030 

1248 



read 
read 
read 
read 



6 read 

000008 read 
25 read 

0000006 read 
read 
5748086 read 



5 Tenths. 

7 Hundredths. 
30 Thousandths. 

1248 Ten Thousandths. 

8 and 6 Tenths. 

7 and 8 MiUionths. 
84 and 25 Hundredths, 
5 and 6 Ten MiUionths. 
480. 

585 and 5748086 Ten 
MiUionths. 



Subtraction of Decimals. 

Rule. — Place the numbers directly under each other, 
according to their several values, as in addition ; then sub- 
tract as in whole numbers, and point off the decimals, as in 
the last rule 

Example. — Subtract 7-75 from 15-135. 

15-125 

7-75 



7 "375 remainder. 



summary of arithmetic, 169 

Multiplication of Decimals. 

Rule. — Place the factors under each other, and multiply 
them together as in whole numbers ; then point off as many 
figures from the right hand of the product as there are 
decimal places in both factors, observing, if there be not 
enough, to annex as many ciphers to the left hand of the 
product as will supply the deficiency. 

Example.— M.ultii>lj 3-625 by 2-75. 

3 -625x2 -75 =9 -96875. Ans. 

Division of Decimals. 

Rule. — Prepare the decimal as directed for multiplication; 
divide as in whole numbers ; cut off as many figures for deci- 
mals in the quotient as the number of decimals in the dividend 
exceeds the number in the divisor ; and if tlie places in the 
quotient be not so many as the rule requires, supply the 
deficiency by annexing ciphers to the left hand of the 
quotient. 

Eocample 1 —Divide 173-5425 by 3-75. 

3 -75)173 -5425(46 -37 
1500 

2354 

2250 

1042 
750 

2925 
2625 

300 



170 SUMMARY OF ARITHMETIC. 

Example 2.— Divide 63-50 by 4-25, 

4-25)63-50(14-94 
425 

2100 
1700 



4000 
3825 



1750 
1700 



RULE OF THREE, OR PROPORTION. 

The Rule of Three teaches how to find a fourth propor- 
tional term to three given numbers. 

The rule of three is either direct or inverse. 

When more requires more, or less requires less, it is direct. 
Thus, if 5 barrels of beef cost $30, what will 12 barrels cost? 
Or, if 30 cubic inches of cast iron weigh 8 lbs., what will 878 
cubic inches w^eigh ? 

The proportion in both of the above cases is direct, and the 
statement must be 

As 5 : 30 : : 12 : 4th term=72 Ans. 
30 : 8 : : 378 : " =100| lbs. Ans. 

When more requires less, or less requires more, the rule is 
inverse. Thus, if 3 men do a certain piece of work in 5 days, 
in how many days will 4 men do the like quantity ? Or, if 
12 men build a certain quantity of wall in 28 days, in how 
many :1a ys wUl 8 men perform the same work ? 



SUMMARY OF ARITHMETIC. 171 

Here the proportion is inverse, and the statement must be 
4 : 5 : : 3 : 4th term=3f. Ans. 
^' 8 : 28 : : 12 : " =42. Ans. 

The product of the second and tliird terms, divided by the 
first, always gives the fourth term. 

Three numbers are necessary for a statement ; and two of 
these must contain the supposition, and the third the demand. 

Eule. — Of the three given numbers, place that for the third 
term which is of the same kind with the answer sought. 

Then consider, from the nature of the question, whether 
the answer will be greater or less than this term. If tiie 
answer is to be greater, place the greater of the two numbers 
for the second term, and the less number for the first term ; 
but if it is to be less, place the less of the two remaining num- 
bers for the second term, and the greater for the first ; and 
in either case multiply the second and third terms together, 
and divide the product by the first for the answer, which will 
always be of the same denomination as the third term. 

Note. — If the first and second terms contain different denomina- 
tions, tliey must both be reduced to the same denomination ; and 
compound numbers to integers of the lowest denomination contained 
la it. 

what will 130 tons 



Example. 


— If 40 tons of iron cost 


cost? 






TONS. DOLLS. TONS. 




40 : 450 : : 180 




130 




13500 




450 




4|0)5850|0 



1462-5 dollars. Ans. 



172 SUMMARY OF ARITHMETIC. 



ARITHMETICAL PROGRESSION. 



Arithmetical Progression is a series of numbers which 
succeed each other regulai-ly, increasing or diminishiug by a 
constant number or common difference : 

As 1, 3, 5, 7, 9, &c. ) increasing series. 
15, 12, 9, 6, 3, &c. ) decreasing series. 

The numbers which form the series are called terms. The 
first and the last term are called the extremes, and the others 
are called the means. 

In arithmetical progi'ession, there are five things to be con- 
sidered, viz. : 

1, The first term. 

2, The last term. 

3, The common difference. 

4, The number of terms. 

5, The sum of all the ternu* 

These quantities are so related to each other, that ■when 
any three of them are given, the remaining two can be found 

Given the first tervi, the common difference, and the num 
her of terms, to find the last term. 

Ride. — Multiply the number of terms, less one, by the 
common difference, and to the product add the first term. 



SUMMABT OF ARITHMETIC. 173 

Example. — What is the 20th term of the arithmetical pro- 
gression, whose first term is 1, the common difference ^ ? 
20— 1 = 19 and 19 xi= 9^; and 9i+l=10i. Ans. 

Given the numher of terms and the extremes, to find the 
common difference. 

Rule. — Divide the difference of the extremes by one less 
than the number of terms. 

Example. — The extremes are 3 and 29, and the number of 
terms 14, required the common difference. 

29— 3=26; and 26 -M 3 =2. Ans. 

Given the common difference and the extremes, to find the 
number of terms. 

Ride. — Divide the difference of the extremes by the com- 
mon difference, and to the quotient add one. 

Example. — The first term of an arithmetical progression is 
11, the last term 88, and the common difference 7. What is 
the number of terms ? 

88—11 = 77; and 77-^7=11 ; 11+1 = 12. Ans. 

Given the extremes and the number of terms, to find the 
sum of all the terms. . 

Bide. — Multiply half the sum of the extremes by the num- 
ber of terms. 

Example. — How many times does the hammer of a cljck 
strike in 12 hours ? 

l-(-12=13 the sum of the extremes. 
Then 12 X (13 -^2) =78. Ans. 



174 RULE FOR SETTING 



TO SET THE VALVES OF A CORLISS 
ENGINE.* 



And make proper adjustment of valve gear and regulator, 
please read carefully and follow the instructions here given : 

The Steam and Exhaust Valves. — Take off the back 
valve chest cover or bonnets and upon the bore of the seats 
you will find a mark which is in line with, or coincides with 
the closing edge of the port for that particular valve seat. 
Look upon the end of the valve and find a mark running 
towards the centre of the valve ; this line coincides with the 
closing edge of valve. Note that in case of the exhaust 
valve, the valve controls the part leading into the exhausi 
passage and not the opening from the cylinder downward 
The upper edge of the exhaust port is the closing edge an(? 
the outer edges of the steam ports are the closing edges. 

The Wrist Plate — should now be looked over and you 
will find a mark upon the hub of the same, and correspond- 
ing marks upon the hub of the wrist plate bracket. Also 
marks which show the full extent of motion of the wi-ist 
plate when it is moved back and forth by the eccentric. The 
wrist plate should be located exactly central between the 
four valves and is so placed in the shop in building the 

* These directions are given by E. P. Hampson to accompany the 
Eclipse Corliss Engine, and are sufficiently general to answer for any 
Corliss Engine. 



CORLISS ElMGINE VALVES. 175 



machine, and all adjustments are made and valves properly 
set, but in taking apart for adjustment it may be possible 
that the adjustments may be distributed and need careful 
going over before attempting to start the engine for the first 
time. 

To Test the Marks on Wrist Plate Hub — connect the 
eccentric rods and engage or drop the carrier rod back upon 
the wrist plate stud ; then turn the eccentric upon the shaft, 
the full extent of its throw or vibration each way, and 
observe if the marks upon the hub of wrist plate at full 
throw agree with the marks upon the bracket ; if not, dis- 
connect the strap from eccentric rod, and adjust the screw 
on stub end by lengthening or shortening, as required, until 
the marks do agree on both extremes of movement. Now 
you are ready 

To Set the Valves. — Place the wrist plate in a vertical 
position (at the central mark) ; turn the valves around in 
their seats until the steam valves show by the closing edge 
marks upon their ends by comparison with the port line 
marks in the seats, that the steam-valve edges lap over or 
cover the ports I of an inch for 18 inch bore of engine 
cylinder, f for 24-inch cylinder, and -^^ for 30-inch cylinder. 
The exhaust valves should show from ^V ^o I '^P' ^^- 
cording to size of cylinder. 

In Connecting the Wrist Plate — see first that the cut-off 
latch is hooked on the stud or is engaged. Leave the plate 
and valves in this position and adjust the length of the wrist 
plate rods to suit the distances between the studs, or, in other 
words, connect the wrist plate and steam and exhaust valve 



176 RULE FOR SETTING 

arms so the wrist plate stands at the central mark or vertical, 
and the steam and exhaust valve have the proper lap and 
opening as instructed, the proper amount of steam lap and 
exhaust opening being determined by the size of the engine. 

To Make Final Adjustments. — Now you can drop the 
wrist plate carrier rod hook on the stud, place the engine 
upon the centre, knowing ■which way the engine shaft is to 
run, turn the eccentric upon the sliaft, it being loose, in the 
same direction in which the shaft is to run, a little more 
than at right angles ahead of the crank or until the steam 
valve on the same end as the jaiston is just beginning to open, 
say -^^ of an inch — in this position secure the eccentric on the 
shaft by means of the set screws in the hub. (See in aU 
cases that the steam valves are hooked up or engaged by the 
cut-off mechanism.) Then turn the engine on the opposite 
centre and see if the steam valve on that end has the same 
amount of opening ; if not, you can make the adjustment by 
lengthening or shortening the wrist plate rod attached to 
this valve. 

To Adjust the Cut-Off, see that the governor and 
connections are put together properly, and block the gover- 
nor about half way in the slot ; then fasten the reach or cam 
rod lever so it stands about at right angles to a line drawn 
midway between the reach rods ; then lengthen or shorten 
the reach rods until the cam or trip levers stand vertical or 
plumb. The governor and connections now occupy the 
proper relative positions, and it remains to make the 

Exact Adjustment and to equalize the cut-off, so the 
game amount of steam is admitted at each end of the stroke-. 



CORLISS ENGINE VALVES. -(77 



Also, lower the governor and observe when the governor is 
down that the cut-off mechanism does not unliook but allows 
steam to be taken full stroke,* after wliich place the engine 
at, say I of the stroke, which can be done by measuring upon 
the shde ways from each end and turning the engine (icith 
all parts connected up) until crosshead is fair with the mark, 
then slowly raise the governor until the cut-off on the end 
taking steam trips or unhooks, and to insure this point 
being accurately determined, it is well to stand by with the 
hand pressing down upon the dash-j)ot rod ; now block the 
governor in this position and try the cut-off on the other 
stroke same distance from the end. After a few trials back 
and forth and adjusting the length of the cam rods, the 
cut-off can be made to drop at precisely the same point of 
stroke. Take care to secure everything permanently v^hen 
done. 

The Dash-Pot Rod should be adjusted in length so the 
steam valve arm resting thereon, when the dash-pot plunger 
is home, or at the bottom of the pot, is in such a position 
that the latch is sure to hook over the latch stud, and the 
stud lays midway between the latch die and the closing 
shoulder. This will insure, on the other hand, the positive 
engagement of the latch, and on the other hand prevent the 
she alder from jamming down upon the latch stud in steam 
arm. If the dash-pot rod is too short the latch will not hook 
on. Look out for this. 



* Here we would say that it does not appear to be generally known 
that the Corliss valve motion, when properly made, is provided with 
a positive closing device which, in case the valve does not trip, posi- 
'Vely closes the valve before piston reaches the end of the stroJie, 



178 CORLISS ENGINE VALVES. 

The Dash-Pot is provided with a leather packing in the 
vacuum plunger underneath the dash-pot proper. This should 
be kept in good condition. To spread the packing introduce 
some liners of paper inside the flange or cup leather. When 
leather is adjusted just right the pot works promptly and 
softly. The air valve in the air opening is to regulate the 
amount of air cushion by turning the screw in the escape 
hole. 

The Regulator Gag-Pot is used on Corliss engines to 
prevent over-sensitiveness of the governor, and to its re- 
sponse to trivial changes. Use only coal or kerosene oil in 
this pot, and remove one or more of the screws in the piston 
to give freedom of motion. See that all parts of the gover- 
nor move freely. 

Using a Steam Engine Indicator to test the correctness 
of valve setting is the most approved method known, and 
should be applied in cases where an indicator can be obtained. 
Recollect that to adjust the point of cut-off to take same 
amount of steam to each end, adjust the cam or reach rods. 
To give more or less lead adjust the wrist plate rods. 
Lengthening them increases the lap, and shortening them 
gives more lead. The same with the exhaust valves, the 
cushion or release being affected thereby. If the eccentric 
is properly set it is not necessary to disturb it in ordinary 
cases. In closing these directions, let us impress upon you 
the necessity of marking everything, so at a glance you cau 
teU if it has been disturbed. 



i 



RULES USEFUL TO THE ENGINEER. J 79 

Emergency Rule for Setting Slide Valves. 

If the eccentric slips around the shaft, or any other acci- 
dent throws the valve-gear out of position, then, 

1. Have some one roll the engine forward in the direction 
it runs until the crank is on the dead centre. 

2. Open the cylinder cocks at each end. 

3. Admit a small amount of steam into the steam chest by 
opening the throttle slightly. 

4. Roll the eccentric forward, in the direction the engine 
runs, until steam escapes from the cylinder cock at the end 
where the valve should begin to open. 

5. Scre^v your eccentric fast to the shaft. 

6. Roll your crank around to the next centre, and ascertain 
if steam escapes at the same point, at the opposite end of the 
cylinder. If so, the valve is in position for service, until an 
opportunity occurs to open the steam-chest and examine the 
valve-gear. 

Emergency Rule for Setting Duplex Pump Valves, 

Take off the valve chest cover, push the piston to water 
end, mark the piston rod by tying a string at the gland, then 
push same piston to stem end and tie another string around 
it. Find the center between the two marks and move the 
piston until the centre mark reaches the gland where the 
first mark was made. After this is done see how the valve is 
for lead ; if equal at both ends your valve is set, if not, adjust 
your jam nuts to suit. Work the same way with the other 
piston. 



180 A PRELIMINARY EXAMINATION. 



A PRELIMINARY EXAMINATION CONDUCTED 
BY ONE'S SELF- 



1. Can I build and maintain a fire with an in*^ensity of 
heat sufficient to liold a working pressure of steam ? 3. Can 
I fire with soft coal and prevent smoke issuing from my 
chimney in too large volumes ? 3. Can I pack the valve 
stems, chest covers and piston rods of the engine and feed 
pump ? 4. Can I line up shafting ? 5. Can I lace up a belt 
in a suitable manner and run it on the pulley safely ? 6. Do 
I understand, and can I replace the working points of the 
feed pump when they become worn ? 7. Can I determine, 
by its action, whether i)ump is delivering water to the boiler 
or not ? 8 If not, can I tell where the difficulty exists ? 

A chief engineer's position is no sinecure. It reqtiires 
constant study, thought and action. It takes men of hard 
brains to fill soft situations, it also requires years of applica- 
tion for brains to harden, hence one too young or inexperi- 
enced should hesitate in accepting a position which they 
know they cannot possibly fill with mutual profit to them- 
selves or the owners. 

l^lementary and Preliminary Questions hy the 
Examining Engineer. 

These questions are given as those frequently asked of the 
applicant upon his first appearance for examination. 

i. Where and how long did you serve in the works at the 
making or at the repairing of engines and in what capacities? 



A PBELIMINABY EXAMINATION. 181 

2. How long have you served as fireman ? How long have 
you been employed as an engineer, and where? '6. Give 
some further idea of the extent of your experience as an 
engineer. 4. What kind of engines are you familiar with ? 
Marine or land, condensing or non-condensing, horizontal, 
compounds, etc? 5. What defects in engines have come 
under your notice ? 6. What caused these defects and how 
were they remedied ? 7. With what description of boilers 
have you served ? 8. Describe a horizontal tubular boiler. 
9. Describe a vertical boiler. 10. What boiler defects have 
come under your notice and how have they been remedied ? 
] 1. Have you ever witnessed a steam boiler explosion, and if 
so, give the cause ? 13. Give the names of the firms for 
whom you have served or vessels upon which you have been 
engaged ? 13. What parts of the engine are usually of cast 
iron ? 14. For what parts of an engine is steel sometimes 
used? 15. What are hand holes put in boilers for ? 16. How 
often do you open them ? 17. What is the shape of a man 
hole cover, and about what is its size ? 18. What is priming 
in a boiler and what means are taken to prevent it ? 



Note. — A boilermaker says that never before have boiler materials 
been of better quality than they are to-day. A contrary belief is often 
expressed ; but modern mastery of steel making has lessened the mar- 
gin between good steel and inferior steel. The danger with boiler 
making is not poor steel, but poor workmanship. Badly spaced tubes, 
rivets and braces, plates too thin for the work, deficient safety attach- 
ments, and ill-proportioned settings are points where the ignorant or 
dishonest make a cheap and dangerous boiler. 



182 XT. S. RULES FOB SAFETY VAl^VMS, 



U. S. GOVERNMENT RULES FOR THE SAFETY 
VALVE. 



The following rules issued by the United States Board of 
of Supervising Inspectors, on account of changes in the rules 
for granting licenses to engineers of steam vessels, are 
entirely accurate for use in figuring the different problems 
relating to the safety valve. 

To find the weight required to load a given safety-valve to 
blow at any specified pressure. 

1. Measure the diameter of the valve, if is it not known, 
and from this compute its area exposed to pressure. 

2. Weigh the valve and its spindle. * If it is not possible 
to do this, compute their weight from their aimensions as 
accurately as possible. 

3. Weigh the lever, or compute its weight from its dimen- 
sions. 

4. Ascertain the position of the centre of gravity of the 
lever by balancing it over a knife-edge, or some sharp-cor- 
nered article, and measuring the distance from the balancing 
point to the fulcrum. 



* To find the weight of the valve, spindle, lever, etc., proceed as fol- 
lows : Take out the valve and spindle and weigh them and make a 
note of it, then put them back in place, connect the lever and drop it 
in place resting on the valve spindle, tie a string to the lever directly 
over the spindle, hook on the scales to the string and weigh the lever, 
to the weight of the lever add the weight of valve and spindle, or the 
weight may be found approximately by computatiou. 



U. S. RULES FOB SAFETY VALVES. 183 



5. Measure the distance from the center of the valve to 
the fulcrum. 

6. Measure the distance from the fulcrum to the center of 
the weight. 

Then compute the required weight as follows : 

1. Multiply the pressure in pounds per square inch at which 
the valve is to be set by the area of the valve in square 
inches; set the product aside and designate it "quantity 
No. 1." 

2. Multiply the weight of the lever in pounds by the dis- 
tance in inches of its center of gravity from the fulcrum ; 
divide the product by the distance in inches from the center 
of the valve to the fulcrum, and add to the quotient the 
weight of the valve and spindle in pounds ; set the sum aside 
and designate it " quantity No. 2." 

3. Divide the distance in inches from the center of the 
valve to the fulcrum by the distance, also expressed in inches, 
from the center of the weight to the fulcrum ; designate the 
quotient "quantity No. 3." 

4. Subtract quantity No. 2 from No. 1, and multiply the 
difference by No. 3. The product will be the required weight 
in pounds. 

To find the length of the lever, or distance from the fulcrum 
at tvMch a given weight vnust be set to cause the valve to blow 
at any specified pressure. 

The area of the valve in square inches, the weight of the 
valve, spindle and lever in pounds, the position of the center 
of gravity of the lever, and the distance from the center of 



184 U. S. RULES FOB SAFETY VALVE& 

the valve of the fulcrum, must be known, as in the first 
example. 

Then compute the required length as follows 

1. Multiply the area of the valve in square inches by the 
pressure in pounds per square inch at which it is required to 
blow ; set the product aside, and designate it " No. 1." 

2. Multiply the weight of the lever in pounds by the dis- 
tance in inches of its center of gravity from the fulcrum ; 
divide the product by the distance in inches from the center 
of the valve to the fulcrum ; add to the quotient the weight 
of the valve and spindle ; set the sum aside, and designate it 
"No. 2." 

3. Divide the distance in inches from the center of valve 
to fulcrum by the weight of the ball in pounds, and call the 
quotient " No. 3." 

4. Subtract 'No. 2" from "No. 1," and multiply the 
difference by "No. 3 "; the product will express the distance 
in inches that the ball must be placed from the fulcrum to 
produce the required pressure. 

To find at what pressure the safety valve tmll comncence to 
hlow when the weight and its position on the lever are known. 

The weight of valve, lever, position of centre of gravity of 
lever, etc. , must be known as in both the preceding examples. 

Then compute the pressure at which the valve will blow, 
as follows : 

Multiply the weight of the lever by the distance of Its 
center of gravity from the fulcrum ; add to this product that 
obtained by multiplying the weight of the ball by its distance 



U. S. RULES FOR SAFETY VALVES. 1S5 

from the fulcrum ; divide the sum of these t-wo products by 
the distance from the center of the valve to the fulcrum, and 
add to the quotient so obtained the weight of the valve and 
spindle. Divide the sum by the area of the valve ; the 
quotient will be the i-equired blowing-off pressure in pounds 
pet square inch. 

Example. 

Suppose v^e have a safety valve, with a weight of 50 lbs . 
suspended 24 inches from the fulcrum ; say the lever weighs 
6 lbs., gravity center (balancing point) 15 inches from the 
fulcrum, weight of valve and spindle 2 lbs. , and its center 4 
inches from the fulcrum, and the diameter of the valve 2 
inches, at what pressure will the valve open ? Now, then: 

Diameter of valve is 2 inches ; its square is 2x2=4 ; its 
area is 0.7854x4=3.1416; the weight of the ball is 50 lbs., its 
distance from fulcrum is 24 inches, and 50x24=1,200 ; the 
weight of lever is 6 lbs., the center of gravity is 15 inches 
from the fulcrum, and 15x6=90 ; the weight of the valve is 
2 lbs., and its distance is 4 inches from fulcrum, and 4x2=8; 
the area of the valve is 3. 1416, and its center is 4 inches from 
fulcrum, then 4x3.1416=12.5664, and 1200-1-90+8=1298, and 
1298 divided by 12.5664=103.3 lbs., or the pressure at which 
the \alve will open*. 



* The " moment " or leverage of tlie steam, is the total pressure 
acting upwards, multiplied hy the distance iu inches from the pivot 
to the valve-stem. The moinent or leverage of the ball acting down- 
wards ia the total weight of the ball multipled by the distance in 
toches from the pivot to the center support of the ball. When, there- 
tore, the moment of the steam, which acts upwards, exceeds both the 
dead weight of the lever and valve, and also the moment of the ball 
I>Oldini^ the valve down, then the valve rises and steam escapes. 



186 U. S. GOVERNMENT RULES. 



U, S. GOVERNMENT RULES FOR EXAMINA- 
TIONS OF APPLICANTS FOR ENGINEERS' 
LICENSES. 



It will be observed that in land service the engineer is ex- 
amined with reference to his capacity to manage a particular 
steam plant, especially the steam generating apparatus. He 
is licensed to have charge of a particular "plant" and for a 
single year ; but in the marine service, where the examina- 
tions are conducted by sworn officers of the U. S. Navy, the 
license is granted without reference to a particular craft, 
nor is it limited to time, except the candidate is subject to 
re-examination; the marine licenses, however, vary as to 
ocean and inland steamers, tug boats, etc. 



Regulations Relating to Marine Engineers. 

1 . Before an original license is issued to any person to aol 
as engineer, he must personally appear before some local 
board or a supervising inspector for examination ; but upon 
the renewal of such license, w^hen the distance f roui any local 
board or supervising inspector is such as to put the person 
liolding the same to groat inconvenience and expense to 
appear in person, he may, upon taking the oath of office be- 



ENGINEERS' EXAMINATlONls. 187 

fore any person authorized to administer oaths, and forward- 
ing the same, togetlier with the license to be renewed, to the 
local board or supervising inspector of the district in which 
he resides or is employed, have the same renewed by the 
said inspectors, if no valid reason to the contrary be known to 
them; and they shall attach such oath to the stub end of the 
license, which is to be retained on file in their office. And 
inspectors are directed, when licenses are completed, to draw 
a broad pen and red ink mark through all unused spaces in 
the body thereof, so as to prevent, so far as possible, illegal 
interpolation after issue. 

3. The classification of engineers on the lakes and sea- 
board shall be as follows : 

CHIEF. 

Chief engineer of ocean steamers. 

Chief engineer of condensing lake, bay and sound steamers. 
Chief engineer of non-condensing lake, bay and sound 
steamers. 
Chief engineer of condensing river steamers. 
Chief engineer of non-condensing river steamers. 

Chief engineer of condensing freight, towing, and fishing 
steamers. 

Chief engineer of non-condensing freight, towing, and 
fishing steamers. 

Chief engineer of condensing steamers under one hundred 
tons. 

Chief engineer of non-condensing steamers under one hun- 
dred tons. 
Chief engineer of canal steamers. 



188 U- S. GOVERNMENT RULES. 

FIRST ASSISTANT. 

First assistant engineer of ocean steamers. 

First assistant engineer of condensing lake, bay, and sound 
steamers. 

First assistant engineer of non-condensing lake, bay, and 
sound steamers. 

First assistant engineer of condensing river steamers. 

First assistant engineer of non-condensing river steamers. 

First assistant engineer of condensing freight, towing, and 
fishing steamers. 

First assistant engineer of non-condensing freight, towing, 
and fishing steamers. 

First assistant engineer of condensing steamers under one 
hundred tons. 

First assistant engineer of non-condensing steamers under 
one hundred tons. 

First assistant engineer of canal steamers. 

SECOND ASSISTANT. 

Second assistant engineer of ocean steamers. 

Second assistant engineer of condensing lake, bay, and 
sound steamers. 

Second assistant engineer of non-condensing lake, bay, and 
sound steamers. 

Second assistant engineer of condensing river steamers. 

Second assistant engineer of non-condensing river steam 
ers. 

Second assistant engineer of condensing freight, towing 
and. fishing steamers. 

Second assistant engineer of non-condensing freight, tow 
itig and fislung steamers. 



ENGINEERS' EXAMINATIONS. J 89 

Second assistant engineer of condensing steamers under 
one hundred tons. 

Second assistant engineer of non-condensing steamers 
imder one hundred tons. 

THIRD ASSISTANT. - 

Third assistant engineer of ocean steamers. 

Third assistant engineer of condensing lake, bay, and 
sound steamers. 

Third assistant engineer of non-condensing lake, bay, and 
sound steamers. 

Third assistant engineer of condensing river steamers. 

Third assistant engineer of non-condensing river steamers. 

Third assistant engineer of condensing freight, towing, and 
fishing steamers. 

Third assistant engineer of non-condensing freight, towing 
and fishing steamers. 

First, second, and third assistant engineers may act as 
such on any steamer of the grade of which they hold license, 
or as such assistant engineer on any steamer of a lower grade 
than those to which they hold a license. 

Inspectors may designate upon the certificate of any chief 
or assistant engineer the tonnage of the vessel on which he 
may act. 

3. Assistant engineers may act as chief engineers on high- 
pressure steamers of one hundred tons burden and under, of 
the class and tonnage, or particular steamer for which the 
inspectors, after a thorough examination, may find them 
qualified. In all cases where an assistant engineer is per- 
mitted to act as first (chief) engineer, the inspector shall state 



190 V- S. GOVERNMENT RULES. 

on the face of his certificate of license the class and tonnage 
of steamers, or the particular steamer on which he may so 
act. 

4. It shall be the duty of an engineer when he assumes 
charge of the boilers and machinery of a steamer, to forth- 
with thoroughly examine the same, and if he finds any part 
thereof in bad condition, caused by neglect or inattention on 
the part of his predecessor, he shall immediately report the 
facts to the local inspectors of the district, who shall there- 
upon investigate the matter, and if the former engineer has 
been culpably derelict of duty, they shall suspend or revoke 
his license. 

5. No person shall receive an original license as engineer, 
or assistant engineer, except for special license on small 
pleasure steamers of ten tons and under, and ferry boats 
navigated outside of ports of entry and delivery, who has 
not served at least three years in the engineer's department 
of a steam vessel. 

Section 5. (Second paragraph amended.) Provided, That 
any person who has served as a regular machinist in a marine 
engine works for a period of not less than three years (not 
including any time he may have served as an apprentice, 
may be licensed as an engineer of steam vessels of one hun- 
dred tons and under, and for inferior grade of license above 
one hundred tons); and any person who has served for a 
period of not less than three years as a locomotive engineer 
stationary engineer, regular machinist in a locomotive or 
stationary engine works (apprentice machinist in an engine 
works), and any person who has graduated as a mechanical 



ENGINEERS'' EXAMINATIONS. 191 

engineer from a duly recognized school of technology, may 
be licensed to serve as engineer on steam vessels after having 
had not less than one year's experience in the engine depart- 
ment of a steam vessel, which experience must have been 
obtained within tw^o years preceding the application (which 
fact must be verified by the certificate in writing of the 
licensed engineer or master under whom the applicant has 
served, said certificate to be filed with the application of the 
candidate), and no person shall receive license as above, 
except for special license, who is not able to determine the 
weight necessary to be placed on the lever of a safety valve 
(the diameter of valve, length of lever, and fulcrum being 
known) to withstand any given pressure of steam in a boiler, 
oi' who is not able to figure and determine the strain brought 
on the braces of a boiler with given pressure of steam, the 
position and distance apart of braces being known ; such 
knowledge to be determined by an examination in w^riting 
and the report of the examination filed with the application 
in the office of the local inspectors, and no engineer, or 
assistant engineer now holding a license shall have the grade 
of the same raised without possessing the above qualifi- 
cations. 

And no original license shall be granted any engineer, oi 
assistant engineer, who cannot read and write, and does not 
understand the plain rules of arithmetic. 

The Secretary of the Treasury has issued the following 
rules concerning the examination of applicants for the posi- 
tion of second assistant engineer in the United States revenue 
marine. 



192 U. S. GOVERNMENT RULES. 

A candidate for an appointment as second assistant 
engineer must not be less than twenty-one nor more than 
thirty years of age ; he must be of good moral character and 
correct habits ; he must have worked not less than eighteen 
months in a machine shop and have had responsible charge 
of a steam engine, or else have served not less than that 
period in charge or assisting in the care and management 
of the machinery of a steam vessel in active service. Upon 
examination, he must be able to describe and sketch all 
the different parts of the marine steam engine and 
boilers, and explain tlieir uses and mechanical operation, 
the manner of putting thena in action, regulating their 
movements, and guarding against danger. He must write 
a fair legible hand, be well acquainted with arithmetic, 
simple mensuration, English orthography and composition, 
also with rudimentary mechanics and its practical appli- 
cations; he must possess some skill in the use of ordinary 
hand tools, and have a fair practical knowledge of the 
nature of heat and steam, of the general laws in relation 
to the expansion of steam, of the uses of the indicator and 
interpretation of diagrams, of the chemistry of combustion 
and corrosion, of the composition of sea water and uses of 
the salinometer, and of the usual calculations to determine 
loss by blowing, gain by heat, and water necessary for con- 
densation. 

No person otherwise qiialified will be commissioned as an 
engineer before he has shown his ability to perform duty at 
sea in a satisfactory manner for a period of at least six 
months. This service may either antedate or be g,cc[uired 
subsequent to an examination. 



ENGIl^EERS' EXAMINATIONS. 193 

No person will be originally appointed to a higher grade 
than second assistant engineer, not until he shall have passed 
a i^hysical and professional examination. The j)hysical ex- 
amination shall preceed the professional, and if a candidate 
be rejected physically, he will not be examined further. All 
professional examinations will be competitive in character, 
and applicants, who pass the minimum standard required in 
several subjects, will be placed upon the list of persons elig- 
ible for appointment, in the order of the excellence of their 
examinations, respectively. From this list appointments 
will be made in regular order, as vacancies may occur, until 
another examination. 

No person will be designated for examination until he has 
filed in the department the necessary certificates showing his 
proper qualifications as to character, habits, and time or 
times of service, and the ability that has been displayed dur- 
ing such service. 

Any person producing a false certificate of age, time of 
service, or character, of making false statement to a board 
of examination, will be dropped immediately. 

Any person who, subsequent to his examination, may be- 
come disqualified from moral considerations, will not be 
appointed. 



194 CITY ORDINANCE. 



(MODEL OF) 

CITY ORDINANCE RELATING TO ENGINEERS' 
LICENSES. 



The following is given as a model of city regulations re- 
quiring examinations, and as nearly all State and city laws 
are substantially alike, this may suffice to indicate the legal 
requirements to be conformed to by the applicant. The full 
text of the law here given shows very clearly the responsi- 
bility of the system of licensing an engineer and the gravity 
with which it is regarded by the public : 

Sec. 388. Any person desirous of being employed to take 
charge and control of any stationary engine, steam boiler, or 
other steam generating apparatus within the city of Cleve- 
land, shall apply to the Examiner of Engineers for a blank 
application, which shall have been prepared by said Exami- 
ner of Engineers. 

After said applicant shall have filled out said blank appli- 
cation, and shall have caused the same to be signed by three 
(3) reputable stationary engineers, who shall have obtained 
previously a license for said employment, he shall then apply 
to the said Examiner of Engineer^, to be examined by the 
said Examiner of Engineers touching his qualifications for 



ENGINEERS' EXAMINATIONS. 195 



such employment, and if the said Examiner of Engineers, 
after having made an examination, shall have found said 
applicant possessed of the necessary qualifications for said 
employment, he shall give said applicant a certificate to that 
efliect. 

On presentation of such certificate to the City Clerk, and 
the payment to said clerk of the sum of fifty (50) cents for 
the first issue of a license and twenty-five (25) cents for each 
subsequent issue thereof by such applicant, the said clerk 
shall issue to such applicant a license imder the seal of said 
city, authorizing such applicant to take charge and control 
of a stationary engine, steam boiler, or other apparatus for 
generating steam, for the period of one year from the date of 
its issue, and the said clerk shall pay all moneys so received 
by him into the treasury of said city, to the credit of the 
general fund, provided, however, that said Examiner of 
Engineers shall issue no such license to any applicant who 
shall not have had one (1) year's practical experience in said 
employment, except in private dwelling houses. 

Sec. 389. It shall be unlawful for any person or persons 
to take charge and control of any stationary engine, steam 
boiler, or other apparatus for generating steam, except in 
private dwelling houses, without having a license to do so, 
as provided in the foregoing section, which license shall be 
exposed to view in a conspicuous place in the room or place 
containing the boiler, generator, or engine of which such 
person is in charge ; provided, however, that all licenses 
heretofore issued in pursuanc*^ of said original ordinance shall 
continue in force for the period for which they were issued. 



196 CITY ORDINANCE. 



It shall be unlawful for any person or persons, partnership 
or association, company or corporation, knowingly to employ 
or keep in their employ for the purpose of taking charge and 
control of any stationary engine, steam boiler, or other 
apparatus for generating steam, except in private dwelling 
houses as aforesaid, any stationary engineer or other person 
who has not been licensed as above provided and required. 

Sec. 390. It is hereby made the special duty of every 
police officer or patrolman, and the superintendent of police 
is hereby instructed to give the said Examiner of Engineers 
all possible assistance to enforce the provisions of this chapter, 
and for this purpose the police shall have authority to enter 
any shop, factory, mill, store, warehouse, hotel or other 
building or structure in which a steam boiler or engine is 
located, and to demand to be shown the license of the engi- 
neer having charge of said steam boiler or engine. 

Sec. 391. Whoever violates any of the provisions of this 
chapter shall be subject to prosecution before the Police 
Court of said City, and on conviction thereof be fined in any 
sum not less than ten dollars nor more than twenty dollars 
for the first offense, and not less than twenty dollars nor 
more than fifty dollars for the second and each subsequent 
offense. 



INSPECTION OF STEAM BOILEBS- 197 



LAWS RELATING TO THE INSPECTION OF 
STEAM BOILERS. 



According to the laws of the State, every owner, agent or 
lessee, of a steam boiler or boilers, in the City of New York, 
shall annually report to the board of police, the location of 
said boiler or boilers, and, thereupon, the officers in command 
of the sanitary company shall detail a practical engineer, who 
shall proceed to inspect such steam boiler or boilers, and all 
apparatus and appliances connected therewith. 

When a notice is received from any owner or agent that 
he has one or more boilers for inspection, a printed blank 
is returned to him stating that on the day named therein 
the boilers will be tested, and he is asked to make full pre- 
paration for the inspection by complying Avith the following 
rules : 

Be ready to test at the above named time. 

Have boiler filled with water to safety valve. 

Have 13^ inch connection. 

Have steam gauge. 

Steam allowed two-thirds amount of hydrostatic pressure. 



198 INSPECTION OF STEAM BOILERS. 

The following have also been adopted by one or more 
Inspection Companies: 

How to Prepare for Steam Boiler Inspection. 

1. Haul fires and all ashes from furnaces and ash pits. 

2. If time will permit, allow boiler and settings to cool 
gradually until there is no steam pressure, then allow water 
to run out of boilers. It is best that steam pressure should 
not exceed ten pounds if used to blow water out. 

3. Inside of boiler should be washed and dried through 
manholes and handholes by hose service and wiping. 

4. Keep safety valves and gauge cocks open. 

5. Take off manhole and handhole plates as soon as possible 
after steam is out of boiler, that boiler may cool inside suili- 
ciently for examination ; also Tceep all doors shut about 
boilers and settings, except the furnace and ash pit doors. 
Keep dampers open in pipes and chimneys. 

6. Have all ashes removed from under boilers, and fire 
surfaces of shell and heads swept clean. 

7. Have spare packing ready for use on manhole and hand- 
hole plates, if the old packing is made useless in taking off or 
is burned. The boiler attendant is to take off and replace 
these plates. 

8. Keep all windows and doors to boiler room open, after 
fires are hauled, so that boilers and settings may cool as 
quickly as possible. 

9. Particular attention is called to Eule 5, respecting doors 
— ^which should be open and which closed — also arrangement 



INSPECTION OF STEAM BOILEHH. !»« 

of damper. The importance of cooling the inside of the 
boiler by removal of manhole and handhole plates at the 
same time the outside is cooling, is in equalizing the process 
of contraction. 

Issuing CertiGcates. 

These conditions having been complied with, the boiler is 
thoroughly tested, and if it is deemed capable of doing the 
work required of it, a number by which it shall hereafter be 
known and designated is placed upon it in accordance with 
the city ordinance : Failure to comply with this provision is 
punishable by a fine of $25. A certificate of inspection is 
then given to the owner, for w^liich a fee of §2 is paid. 

Tills certificate sets forth that on the day named the boiler 
therein described was subject to a hydrostatic pressure of a 
certain number of pounds to the square inch. The certificate 
tells where the boiler was built, its style or character and 
' ' now appears to be in good condition and safe to sustain a 

working pressure of to the square inch. The safety 

valve has been set to said pressure." A duplicate of this 
certificate is posted in full view in the boiler room. In case 
the boiler does not stand the test to which it is subject, it 
must be immediately repaired and put in good Avorking order 
before a certificate will be issued. 

AppHcants for licenses are very liable to be asked — to test 
their experience in and around steam boilers — some questions 
relating to their inspection ; hence the value of these extracts 
upon the subject. 



aOO CBIEF INSPECTOR'S BEPOBTS. 

IMPORTANT. 

The following tea pages are undoubtedly the raost 
valuable and instructive of any same number of pages 
in this volume. They indicate the path of advance in 
granting licenses for the future, and, with admirable 
modesty, the great benefits which have accrued from a 
wise and faithful administration of j)ublic law, con- 
trolHng engineers' examinations and the granting of 
licenses. It will be happier times when the whole 
country is equally guarded and protected. 



STEAM BOILER INSPECTION AND CERTIFI- 
CATION OF ENGINEERS. 

BY THE SUPERINTENDENT, DEPARTMENT BOILER INSPECTION 
BROOKLYN, N. Y. 



{Extract.) 
In the city of Brooklyn the insiDection of boilers is made 
by a corps of six inspectors. The hydrostatic test is apphed, 
and wherever deemed necessary, a hammer test is added. 
Whenever defects are ascertained, they are caused to be 
remedied or the boiler condemned. 

The inspection of steam boilers and the certification of 
engineers to manage and care for the same are subjects to 
which much thought has been given by the best engineers of 
the country. From the inception of the general idea of 
official boUer inspection to the present date, gr'at strides 



CERTIFICATION OF ENOmEEIiS. 201 

have been made by both national, state and municipal gov- 
ernments in bringing tlie system to perfection, and to throw 
around boilers under their supervision every safeguard that 
human ingenuity could devise. 

The United States government, through its able corps of 
naval engineers, has done much to advance the interests of 
those engaged in this work, having systematized the \vork so 
that the best possible results are attained with the material 
at hand. The individual states are also gradually falling 
into line and are enacting laws provic^ing for the needed 
inspection. 

In the cities of New York and Brooklyn the laws govern- 
ing boiler inspection are similar in general principle, while 
differing in some of the particulars. In both cities the 
bureaus of inspection are a branch of the j)olice dapartment, 
responsible to the commissioner or commissioners of police. 
In the former city, officers are detailed for this work from 
the police force, after having given satisfactory evidence of 
their qualification for this duty, and are under a command- 
ing officer of experience and discretion. 

In the city of Brooklyn, while the inspectors are not 
members of the force, they are entitled to all the privileges 
and subject to the same discipline. The superintendent of 
steam boilers is a position provided for by statute, the quali- 
fications for which are set forth explicitly, and the duties and 
authority expressed in such laws. The examination and 
grading of engineers is discretionary with him, and the 
steam plants in the city are classified and recorded in liis 
office. The aim and desire of the department is to assist anJ 



202 CERTIFICATION OF ENGINEERS. 

encourage the best skill among our engineers, thereby aiding 
the worthy and deserving men, as well as to provide for 
Bteam users the best material for the management of their 
several steam plants. 

The Association of Boiler Inspectors of the United States 
and Canada, following the example set by the United States 
inspectors, hold annual meetings for the interchange of views 
and opinions as to the best method of boiler inspection. They 
have adopted rules which, while not legally binding upon its 
members as are the rules of the latter body, yet place a moral 
obligation for the carrying out of the same. 

It is our proud privilege to he able to say that since tlie 
institution of the inspection of steam boilers in this city, 
there has been no explosion of a steam boiler that had prev- 
iously been inspected by the department. 

The inspectors are always on the alert, and arrests are fre 
quently made for violation of our laws, and the courts by 
their actions sustain and strengthen the hands of the depart 
ment in enforcing the law. • 

The engineers of this city are of great assistance to the 
department in the care of their several plants, and are ever 
ready to assist the department in its work. The steaur users 
as well recognize the importance of the work, and it is the 
desire of the department while enforcing the law to conserve 
their interests wherever practicable. There are some imper- 
fections in our laws that might be corrected, and some action 
will be taken in that direction to the betterment of the 
department and the perfection of the work. 

J^'Y, 1895. W A. POWERS, 



CHTEJf TNSPECTOWS REPORTS, 



SPECIAL REPORT 

OF THE 

NE^i.' York City Steam Boiler Inspection and Engineers' 
Bureau, Jan. 1, 1895, 

ON 

Boiler Inspection and the Ljcenslno of Engineers. 



In the last annual report from this bureau the inadequacy 
of the present method of boiler inspection was commented 



There are but few engineers in New York City who have not met 
Sergeant Washington MuUin, Chief of the Boiler Inspection and 
Engineer's Bureau, of New York City. Thousands of engineers know 
him at sight. For the henefit of those who have not had the pleasure 
of meeting him we herewith present a brief sketch of his active life : 

Officer MuUin was born in the City of Philadelphia, Sept. 29th, 
1837. His parents removed to New York City when he was but eight 
years of age, and he attended the public schools until he had reached 
his sixteenth year, when he was apprenticed In the engine and 
machine works of Abraham Van Ness, where he was working at the 
breaking out of the war. Young Mulliu was among the first to 
respond to his country's call, and assisted in organizing Company "E," 
73d N. Y. Volunteers. He participated in all of the engagements in 
which his brigade took part ; was promoted to first lieutenant, and 
honorably discharged September, 1864; was appointed to the Police 
Department, New York City, September, 1864, promoted to roundsman 
Oct., 1865, to sergeant 1808, and subsequently assigned as Chief of thti 
Boiler Inspection and Engineer's Bureau, February, 1883. 

Schooled as a soldier, he is a strict disciplinarian ; uses mscretion 
in the examination of the many thousand engineers who come before 
him annually to pass the examination preparatory to taking out the 
engineer's license required by law ; never discriminates, treats all 
applicants alike, shows no favoritism, and the engineer who obtains a 
license must pass the necessary examination in a satisfactory manner, 
proving his ability to take charge of and operate a steam plant. The 
competent have nothing to fear in Sergeant Mullin — the ignorant, 
incompetent and intemperate are always rejected. 

The EnQineer^e List, Jan. '86, 



'^04 SPECIAL REPOBT—IMfOKTANT, 

upon, and recommendations made for a change in the laws 
to improve the system, to the end that the protection to life 
and property be made more secure, and the dangers from 
such casualties as boiler explosions reduced to a minimum. 

While there were several bills presented to the last Legisla 
ture, touching upon the matter of boiler inspections and 
licensing of engineers, none seemed to meet with approval, 
and all failed of passage. 

Therefore, it is again respectfully submitted that, in con- 
sequence of the danger to life and property, attendant upon 
the operation of steam boilers, it would seem that no difficulty 
should be encountered in the endeavors made to have them 
legally regulated as to their proper and careful construction 
and inspection, as well as to the licensing of those who are 
to have charge and operate them, more especially in locali- 
ties which are thickly populated, and where an explosion of 
a steam boiler means dire disaster. 

As a flatter of comparison hetiveen the different places in 
the United States, where there are inspection laivs and where 
no legal supervision exists, it will he noted that the casual- 
ties resulting from boiler explosions are as one to a hundred. 
If the importance of tliis matter was properly and intelli- 
gently impressed upon the consideration of those selected 
to make the laws, and more stringent safeguards were drawn 
around the la^t^s and ordinances now in force, a much greater 
percentage would be shown in favor of legal supervision. 

The boiler- inspection laws now in operation in the cities 
of New York and Brooklyn, as far as the particular method 
of inspection is concerned, are the same as those existing in 



SPECIAL REPORT-IMPORT Ay T. 205 



1862, when not more than 2,000 steam boilers were operated 
in the then metropolitan district, comprising the counties of 
New York, Kings, Richmond and parts of Queens and West- 
chester, while now there are uj)ward of 8,000 boilers in use 
in the City of ITew York alone. 

At the time mentioned, and for some years after, the aver- 
age pressure used to operate steam boilers was about fifty 
pounds to the square inch, whereas, at jjresent, owing to the 
advancement and improvements made in machinery and 
other devices necessary for steam to operate have been so 
great that the average pressure carried will equal 100 pounds 
to the square inch, and yet, withal, no legal advancement 
has been made in the matters regulating the testing and in- 
spection of boilers. To be sure, reputable manufacturers 
and builders of steam boilers take the necessary precaution 
in building boilers required to withstand this extra demand 
for increased pressure, but it is to guard against that class of 
firms who construct cheap work, taking chances on the 
safety and security of the boilers they make, that more rigid 
laws should be enacted. 

Such laws should provide that every maker of a boiler 
should issue or give a certificate, setting forth the quality 
and thickness of the material used, its guaranteed tensile 
strength and ductility, the pressure per square inch the boiler 
is designed to carry, and every particular concerning its con- 
struction, and that in the absence of such certificate the ten- 
sile strength of the material should be calculated at 40, 000 
lbs. for iron and 50,000 lbs. for steel plates, when determin- 
ing the safe working pressure. 



806 SPECIAL. REPORT— IMPORTANT. 



The strength and security of a boiler should be determined 
by a series of calculations, based upon established rules, upon 
its various parts, and, when the workmanship and material 
is found to be of good quality, a factor of five should be the 
standard used to determine the safe working pressure to be 
allowed. 

But, in the matter of inferior workmanship or inferior 
material, authority should be given the inspector to either 
condemn the boiler or increase the factor to a degree that 
would insure the utmost safety in the operation of the boiler. 
Then, again, every boiler should be subjected to a hydrostatic 
test before put in actual operation, such a test to be made at 
least once every year thereafter, and in the following 
manner : 

The boiler to be filled entirely with water, a fire lighted in 
the furnace, and the temperature of water brought to at 
least 150 degrees of Fahrenheit, when the boiler should be 
subjected to a hydrostatic j)ressure of one and one-half times 
the steam or working pressure to be allowed per square inch. 
The inspector, after applying the hydrostatic test, should go 
inside the boiler and make a thorough examination of every 
part of the same, and, if the test is not satisfactory, the de- 
fects should be made good, and the boiler re -tested. 

In water-tube boilers, constructed to carry 150 lbs. or more, 
where the factor of safety is generally above seven, the 
pressure should be one and one-quarter times the working 
pressure to be allowed, for the reason that pressure above 
225 lbs. will rupture calking in longitudinal seams of steam 
ixunus. 



SPECIAL BEPOBT-TIUPORTANT. 307 

In determining the working pressure for boilers that have 
been several years in use, the inspector should take into con- 
sideration the age and condition under which it has been 
operated, as well as the thickness, original strength, efficiency 
of riveted joints, etc., and make calculation between what 
was its safe working pressure when new, and the pressure 
now desired, and he should make due allowance for deterio- 
ration, and, if necessary, drill holes to properly determine its 
thickness. 

All boilers should have a composition valve or cock placed 
in the feed line, between the check valve and the boilei% so 
as to permit of overhauling the check when steam is up, if 
necessary. All pipe connections of over one inch internal 
diameter should be attached to the boiler by a flanged joint, 
riveted or bolted. Each boiler should have three gauge cocks 
and a water glass, and the gauge cocks and water column 
should be connected directly to tlae boiler with at least one- 
inch pipe, the lower water pipe to be tapped near the bottom 
of the boiler, and the upper steam pipe connected at the top 
of the boiler, and as far away from where the main steam 
pipe is connected as is practical. 

No other connection should be allowed to be taken from it. 
A blow cock should be placed at the bottom of the lower 
water pipe. The bottom gauge cock should be placed at least 
t^vo inches above the highest heating surface, and the other 
cock placed in proper proportions, so as not to unduly reduce 
the intended steam tipace. 

Each boiler should have a steana gauge that avouM cor 
rectly indicate one-and-a-half times the working pressure 



30B SPECIAL REPORT— IMPORTANl. 

allowed, and one safety valve of sufficient capacity, when 
open, to carry off all the steam the boiler could generate with 
all the other valves closed. 

The blow-off pipe on horizontal tubular boilers, when at- 
tached to the back connection or combustion chamber, should 
be of ample size, but not to exceed two inches internal diam- 
eter, and should be of extra heavy pipe, with malleable fit- 
tings, and protected from the intense heat by a metal sleeve 
or other covering, and, in the absence of such covering, there 
should be a circulating pipe connected with the upper part 
of the boiler to give good circulation and eliminate the 
danger attending the dead end between the blow cock and 
boiler. There should also be a surface blow-off. 

All high pressure boilers of the vertical or locomotive style 
should have a fusible plug placed in the crown sheet. 

Boilers should have two ways of feeding — by a steain pump 
and by an injector ; pumps to be used only when hot water 
is available or the injector out of order. When two or more 
boilers are connected, the inspectors should give particulai 
attention to the connection in the main steana pipe, and see 
that due allowance is made for expansion. 

That a proper record of each boiler may be kept, and that 
it could be at all times easily identified, a plate, bearing the 
official record number of the boiler, should be securely and 
permanently fastened to the boiler in a conspicuous place. 

It should be made the duty of engineers in charge of steain 
boilers, to blow, or cause to blow, at least once each day, the 
safety valve to insure its readiness for iise, and should a 



SPECIAL REPORT— IMPORTANT. 209 

safety valve be found, at the annual inspection, to have been 
tampered with or out of order, the certificate of the person 
in charge should be suspended or revoked. 

Provision should also be niade_that would require an engi- 
neer to go inside his boiler, at least once in three months, to 
cleanse the same, and see that no accumulation of scale or 
corrosion had taken place. By this means the property of 
his employer will be protected, the life of the boiler pro- 
longed, and the loss to life and property averted. 

These are mentioned as some of the provisions that should 
be embodied in a law which, when drafted, would cover the 
necessary requirements more in detail, and which would 
surely meet the approval, and ultimately result to the bene- 
fit, of owner, steam user, engineer, and everybody in any 
way concerned or interested in the use of steam, or the safety 
JO life and property. Respectfully submitted, 

WASHINGTON MTT TTTTM 



210 HA WKINS' AIDS. 



insriDEix: 



Hawkins' Aids to Engineers' Examinations. 



Absolute pressure of steam a.. « 62 

Absorber, tlie .. 140 

Absorption (the) Bystem defined 146 

Action of injector 119 

Action of pump described 106 

Addition of decimals 168 

Advantages of compounding 80 

Agitator (the) use of , 147 

Air for combustion ; how supplied 49 

Hot ; not good to supply furnace • 49 

Machines described 149 

Objections to 149 

Standard for speciflo gravity , 134 

Weight of ; under pressure in a boiler. 61 

Alloy, definition of 26 

Ammonia, advantages of. 143 

Anhydrous 143 

Aqua. 147 

Cycle of compression, condensation, expansion 147-148 

Pump defined 146 

Receiver 146 

Appliances for the operation of a steam boiler. 88 

Aqua ammonia defined 147 

Area of pump pistons 112 

Arithmetic, summary of 166 

Arithmetical signs 165 

Calculations, unit of.. 154 

Prosrression 178 

Automatic cutoff of engines 68 



A well arranged Index doubles the value of a scientific and 
mechanical work ; it is like a guide post to a traveller journeying 
through an unknown country. A good index tells very quickly the 
entire contents of a book— it not only gives the page where particular 
information is to be found, but it forcibly indicates to the student 
those items of necessary knowledge of which he is ignorant and 
which It is best for him to "study up." 



INDEX. 211 

Back press\ire 74 

Valve 85 

Ball valve 85 

Baseline 123 

Bearing bars 58 

Bismuth, speciflc heat of 153 

Bituminous coal, how toflre 43 

Combustion of 48 

Lbs. of water evaporated from and at 213° 50 

Units of heat of combustion 50 

Boiler braces and stays 29 

Fittings 83 

Materials 23 

Plates, qualifications for 24 

plate, thinnest it is desirable to use 53 

Rule to find capacity of 116 

Steam, description .... 21 

Tests 140 

Tubes, how to estimate the diameter of 86 

Boiling, irregularity of 140 

Process of 63 

Braces, arrangement of, in a boiler 31 

How best to make repairs 33 

Materials of which made 81 

Questions and answers relating to 29 

Stays 29 

Stress allowed on 33 

Brass, specific gravity of 137 

Brick, speciflc gravity of 137 

Brine system of refrigeration 144 

System, how the brine is circulated 145 

Tank, how arranged 144 

Brush (in electricity) defined 133 

Brushes ; important rule regarding 133 

Butt-joint, description 56 

Calculations for safety valve 93-97 

Of expansion and contraction of steam boilers 28 

Of strength of seam of steam boiler 56 

Power of steam engine 79 

The mean effective pressure 79 

rapacity of boiler ; rulefor 116 

Capacity, safe rule for pump, 109 

Of steam pump 113 

Of water cylinder 113 

Carbon, units of heat of combustion 60 

Lbs. of water evaporation at 213° 50 

Card, indicator 121 

Caulking, definition of 53 

Centigrade thermometer, description. 153 

Certificates, issuing 199 

(new)granted inN.Y ix 

(refused) in N. Y. City is 

Renewed in N. Y. City La 

OhiiTCoal, specifio gravity of 137 

Check valve 85 

Chemical law on which the absorption system is based 147 

Chemical refrigeration 142 

Chief engineer, rank of. 187 

Otrculation of water in boiler, cause of 46 

Crty Ordinance relating to englnaers' licenses, /model of) 144 



212 tLAWKLN^ 4J3aS. 



Classes of engines ; f8 

Of compound engines ....^...^,. . jou 

Of levers •••• ^i 

Classification of knowledge the key to success .17 

Of steam engines ^^o 

Cleaning a Are, way of - • • 43 

Clearance defined j^ 

Coal, bituminous, how to fire •••;•- J" * Vi;oo tX 

Bituminous, lbs. of water evaporated from and at 213° 50 

Bituminous, units of heat of combustion 50 

Combustion of 5° 

Hard, units of heat of combustion 5o 

Hard, lbs. of water evaporated from and a 1 213° ^ 

Hard, how to fire .*^ 

How much " cold " in a lb. of J-** 

In furnace ; thickness of bed of 4d 

Progress in economical use °° 

Specific heat of ... 15d 

Specific gravityof -i^ 

Cock; definition of a °5 



Gauge. 



42 



Cohesion defined ^^ 

Of water 5^ 

Coke, burns after gas in combustion. |^ 

Lbs. of water evaporated from and at 213° 50 

Total units of heat of combustion 50 

Cold, effect on iron -^ 

How much in a lb. of coal ■'^** 

Cold-short iron or steel fv 

Combustible, definition °i 

Combustion of bituminous coal *? 

Chamber, essentials of ^\ 

Process of ***• ^;^ 

Table of heat of 50 

Commutator defined |?^ 

Composition of water '-^ 

Compound engines, description of ^ 

Eule to calculate horse power .... ou 

Compounding, advantages of °^ 

Compressor, double-acting l** 

Condenser defined.... ^j2 

Submerged and open air -L^J 

Condensing engines. •• rS 

Howtomanage '° 

Conductor ; definition of j~5 

Varietiesof. \^ 

Conservation of energy ^^ 

Constituents of steam -Sji 

Construction of a dynamo ••• ^^ 

Of steam boilers °5 

Contraction and expansion of steel boilers «^ 

Cooling tank ( the > j^ 

Copper, specific heat of ■ |o2 

Specific gravity of « ^2i 

Corliss (The) Engine .°' 

Corliss engine valves ; how to set •■•' * 

Corliss valve, illustration .-^ 

Covering steam pipe ; importance of -i^l 

Crank ; object of the id 

Crowfoot brace. -or 

Cnmhing strength defined • • "*• 



INDEX. 213 

Cycle or circle of ammonia 147 

Cylinder ; definition of 75 

Condensation, how to remedy 77 

Clearance in 70 

Water in, efEect of 74 

Dead centers of engines 88 

How to pass, witiiout jarring 88 

Dead steam 59 

Decimals 166 

Bed cation of the work iii 

Defective diagram . 135 

Diagram, defective 125 

Diagram of an indicator 123 

Results ohtained hy an indicator diagram 123 

Diameter of different tubes ; how to ascertain 86 

Difference between pump and injector 117 

Between steel and iron ■ 26 

Direct acting duplex pump 113 

Direct acting steam pump Ill 

Direct expansion system 144-145 

Di\'ision of decimals 169 

Double acting compressor, defined 149 

Double acting engines 65 

Double acting pump 107 

Double injectors 119 

Double riveting 53 

Drain cocks ; liow to manage 78 

Drainage of pipes 86 

Dry steam 59 

Dry steam as a conductor = 104 

Ductility, definition of 23 

Duplex pumps ; direct acting 113 

Duplex pump ; rule for setting 179 

Duplicate parts, advantage of keeping on hand 83 

Durability oi engines , 69 

Duties of a slide-valve 73 

Dynamos, construction of 130 

bynamo-electrio machine 130 

Dynamo ; general construction 130 

Dynamo "■ trouble," 133 

Eccentric ; how to adjust on a new shaft ^ 75 

Economy in production of steam 66 

Ofsteam 69 

Effect of water in cylinder 74 

Effect on particles of water changing it to steam 63 

Effective Horse Power (E. H. P.) 138 

Elastic limit, definition of 23 

Electric current 127 

Electricity, and electric m.achines ; questions and answers relat- 
ing to 126 

For engineers 126 

Kindsof 128 

Electric machines and circuits ; how to keep in order 130 

Electro magnet 131 

Elementary questions by the examining engineer 180 

Elongation of iron and steel , 52 

Of metals 80 

Energy, definition of 153 

Engine (Steam). 64 

Engine and boiler fittings , 83 

Condensing, how to manage 78 



M14 OA.WKINS' AIDS. 



Engine, Componnd 74 

Difference in high and low pressure 74 

Fixtures ; questions and . answers relating to 83 

How to pass dead center 88 

Slide valve, how to reverse motion 75 

Taking charge of new 88 

What to do before starting an 78 

Engines, automatic 68 

Clearance 70 

High speeds 67 

Pumping 112 

Simplicity desirable 68 

The Corliss 67 

Throttling 68 

Engineers' examinations, N. Y. City ix 

Engineers' certificates renewed in N, Y. City ix 

Engineers' licenses; City Ordinance relating to 194 

Brooklyn, N. Y., official report 200 

Offlcialreport 2<)3 

Engineers' licenses * tfecessary quallhcations to secure 13 

Equalizer (the) 146 

Evaporation per lb. coal in ordinary boiler 40 

Examination, conducted by oneself 180 

Examinations of applicants for U. S. Government engineers' 

licenses ; Kules ^'or 186 

Example for rule V. fc>. marine examination 185 

Exhaust-lap 71 

Exhaust line *. . 121 

Ports, definition 76 

Steam injector 119 

Expansion eugines, principles on which they work 81 

Expansion and contraction of boilers 27 

How to avoid dangers of 28 

^ixedand movable 73 

Of steam 5 gain in the use of. 104 

Of water an changing to Bteam 60 

Of steam, according to pressure 60 

Expansion line 121 

Expansion valve 147 

Explosions, great cause of boiler 41 

Extract from N. Y. Laws relating to qualifications 14 

Factor of safety for fittings 86 

In figuring strength of steam boiler 57 

Fahrenheit's thermometer, description 152 

Feed pump ; design of a . 114 

Fire surface of a boiler ; how proportioned 157 

Firing ; Rules for 45 

First assistant engineers 188 

Fittings for engines and boilers 83 

Flange ; definition of boiler 53 

"Flashing" ; because of 133 

Flow of electric currents 128 

Flywheel 88 

Fly wheel, not needed in locomotive and marine engines 88 

Foot-pounds in a H. P 138 

Force of expansion ; how to calculate 28 

Freezing point 153 

Freezing tank (the) 146 

Fullering defined 53 

Fulton, Robt ctitiv 

Furnace, supply of air to 49 



INDEX. 215 

Gas (coal) lbs. of water evaporated from and at 212* 50 

Gas (coal) units of heat of combustion 60 

Gas, first burns in combustion 48 

Gas, ho w ignited 48 

Generator, in ice making 146 

Gland ; definition 76 

Glass, specific gravity of 137 

Globe valves ; to attach 84 

Gold, specific gravity of 137 

Government (U. 8.) rules tor examination of applicants for engi- 
neers' licenses 186 

Gauges, water 42 

Grate bars 58 

Gravity ; questions and answers relating to 134 

Specific table.... 137 

Gusset-stay 30 

Gusset-stays, riveting of 34 

Hammer-test of Kteam boilers 48 

Hard coal, how to fire 43 

Hard, or anthracite coal — total units of heat of combustion 50 

Heads of boilers, dimensions 55 

H ead-to-head brace 30 

Beat and work 150 

Cause of water circulation 46 

Effect of, on strength of boilers 58 

Effect on iron '. ,<. 21 

Mechanical equivalent of 151 

Of combustion, table of 50 

Of saturated steam 101 

Speci tic 153 

The best non-conductor of 159 

Transferable 15l 

Unitof 154 

Heating and ventilation 155 

Heating surface of steam boilers, efficiency of 38 

High and low pressure engines, difference 74 

High and low pressure steam 62: 

High pressure engines 64- 

h omogeneous, definition 24- 

Eorizontal tubular, advantages of 38 

Horsepower; how to determine 79' 

(H. P.) 138 

Indicated and effective 125' 

Necessary for given pressure 113- 

Of steam boiler, rule 138 

Shown by diagram 124 

Hot-short iron or steel 24 

Hotwater? Will pump lift 109' 

Hydraulic test of steam boilers. 54 

Hydrogen in steam 601 

Total units of combustion ■ .. 60 

Hydrometer; definition of — 138 

Ice making, description 141 

Imperfect insulation; effect of 131 

indicated horse power (I. H. P.) • 138 

Indicator card 121 

How to measure easily 12S 

Indicator diagram 123 

General principles of 120 

Questions and answers relating to 120 

Initial pressure of steam , 63 



aiff HA-WKUfS" .4JD& 



Injector or inspirator, defined < 117 

Exhaust steam 119 

Howtoconnect o 118 

Injector; Modeof working J 119 

And pump; difference between 117 

Inspection of steam boilers ; laws relating to the 197 

Sup't Parker's report 5J00 

Insulation; definition of 131 

Necessityof careful 130 

Iron, defl.nition 35 

Elongation of 24 

Difference between, and steel 25 

Hot-short and cold-short 24 

Specific heatof ■, 153 

Specific gravity of 137 

Tensile strength of. 25 

Jaw-brace . 80 

Kinds of electricity 128 

Knowledge (classification of) the key to success 17 

Lap-joint, description , 56 

Lap — why given a valve 72 

Latent heat of steam 103 

Lawof expansion of steam under pressure 61 

Laws relating to the inspection of steam boilers 197 

Laws relating to ventilation, air, etc 156 

"Lead", how to set valve for — 71 

Lead, specifio heat of 153 

Specific gravity of 137 

Leakage around boiler tubes, cause of..o 96 

Leakypiston; totestfor 77 

Pumps Ill 

Slide valve; totestfor 77 

Length of lever for valve to blow at given pressure 183 

Lever; how to calculate power of 93-97 

Kinds and classes of 93 

Licensing of engineers; N. Y. City report 203 

Brooklyn, N. Y., practice 

License, necessary qualifications to secure — 13 

Licenses granted, renewed and i-ejected (official report) ix 

Lift of valves 115 

Limit of lift to a pump 108 

Live steam 59 

Location of safety valve 90 

Locomotive boilers, peculiarity of 40 

Engines 65 

Howtofire a 44 

Loss in water for engine ; provision for 115 

Low pressure steam 62 

Low water: what is to be done in case of 42 

Lugs; definition of 54 

Magnet; electro 13 

Permanent. • 13 

Malleable metal 23 

Marine boilers; peculiarity of 40 

Engines 65 

Marine engineers ; regulations relating to 186 

Mean effective pressure; how to find 79 

Table 80 

Measures and weights 154 

Mochaiucal equivalent of heat -^ 151 

Rftfrigeratinn ,.f.... •••••. 1^ 



INDEX. ai7 

Mercury ; specific gravity of 1S7 

Specific heat of 153 

aiullins, Washington ; sketcli of life 203 

Multiplication of decimals 169 

New steam plant ; first thing to be done in taking charge 158 

Nominal horse power (N. H. P.) 138 

Non-condensing engines 64 

Non-conductors. 139 

Non-conductor of heat ; the best 159 

North pole of electro magnet 131 

" North West " steamer, description of engines 81 

Number of indicator spring 132 

N. Y. City Laws, extract relating to qualifications 14 

Report for 1893 ix 

Bureau of boiler inspection 203 

Oil, for lubrication of engine 78 

Open air condenser defined ] 46 

Ordinates ; how to measure easily 124 

Overstraining of steam boilers 84 

Oxygen in steam 60 

Petroleum, lbs. of water evaporated from and at 312° 50 

Units of heat of combustion 50 

Physical properties of steam 59 

Pipes, how to cure cracking and pounding 86 

Fioe rule for approximate size 114 

Covering ; importance of 158 

Threads 87 

Pfping of a mill or factory 156 

Piping, first thing to be examined 158 

Pitch line of rivet work 54 

Planimeter ; description of 125 

Plates of boilers ; thickness of 55 

Points (4) shown by an Indicator 123 

Poles of permanent or electro magnets 131 

" Pop " safety valve ; definition of 90 

Ports ; steam ; definition 76 

Portable engines 65 

Pressure allowed by inspectors 56 

Initial, of steam 62 

Mean effective, how to find 79 

Terminal, of steam 63 

Prevention of pmoke 160 

Priming of steam boiler 140 

Proportion ; rule of 170 

Pumps ; description of different 105 

Action of, described.. 106-107 

Double and single acting 107 

llow to set up and order 110 

Pistona; area of 113 

Steam and water ends of a 107 

That leak Ill 

Treatment of, in cold weather 110 

Valves; size and lift 108,115 

Questions and, answers relating to 107 

Pump and injector ; difference between. 117 

Pumping engines 112 

Quadruple expansion engines 81 

ualifications for boiler plates 24 

Qualifications (3> necessary to secure engineer's license 13 

Questions (elementary) by the examining engineer , 180 

QueationfJ and answers relating to boiler braces and stays 8P 



218 HAWKINS' AIDS. 



Questions and answers relating to Circulation of water in boilers 46 

Combustion of coal 48 

Construction and strength of 

steam boilers 53 

Electricity and electrie ma- 
chines 127 

Engine and boiler fittings 83 

Expansion and contraction of 

steam boilers 33 

Firing 43 

Gravity and strength of ma- 
terials 134 

Heat and work 151 

Heating and ventilation 157 

Incrustation and scale 35 

Indicator 121 

Materials for boilers 23 

Physical properties of steam. 59 

Pumps 107 

Refrigeration 143 

Safety valve 89 

Smoke prevention 160 

Steam Boiler 38 

Steam engine 67 

Steam injector 117 

Reaumur thermometer, scale 153 

Reducing valve 85 

Refrigerant, defined 143 

Refrigerate, defined 143 

Refrigerating machine 143 

Refrigeration ; questions and answers relating to 143 

Direct and expansion systems 144 

Regularity of speed 69 

Regulations relating to marine engineers 186 

Relief valve 84 

Repairs to braces, how best made 33 

Repellant property in steam . 63 

Report of Chief Inspectors, New York and Brooklyn 200 

Results obtained from diagram 123 

Rivet holes ; pitch of 55 

Location of 54 

Riveting ; kinds of 53 

Rivets, size used in joining sheets 53 

Rotary engines 65 

Rule for ascertaining number and size of stays needed 33 

Calculating power of steam engine 79 

Calculating strain on boiler stays 33 

Capacity of boiler 116 

Capacity of water cylinder 113 

Estimating H. P. of steam boiler.. 140 

Figuring safety valves 93-97 

Finding water capacity of horizontal steam boiler 116 

Finding capacity of pump per hour 113 

Finding horse power necessary to pump water to a giv- 
en height tl3 

Finding the specific gravities of solids 136 

Finding the total heat of steam 102 

Finding water pumped in one minute 113 

Reverse motion of a slide valve engine 75 

Size of pipe for steam U.4 

Rule of Proportion, and examples l7l 

Three 170 



INDEX. 219 

Rules for Firing 45 

Setting up a steam pump 116 

Size of safety valve 91 

(U. S.) ; setting safety valves 183 

Rusted spots in pipe ; how to treat — 86 

Safety ; factor of, for fittings 86 

Safety valve ; Government rules for the 183 

Danger of sticking 89 

Definition of a 89 

Location and size 90 

Safety valve Problems ; how to solve arithmetically 94 

Rules for size of 91 

Salinometer, defined 136 

Salt, amount in sea-water 136 

Sand ; specific gravity of 137 

Saturated steam 59 

Heatof 103 

Table of properti iS of 98 99 

Scale; different kinds of boiler 35 

Scum-cock ; action of 36 

Seam ; strength of riveted 56 

Second assistant engineers 188 

Setting a pump valve ; rules for 1-0 

Shearing strength, definition of 23 

Signs, arithmetical 165 

Silver, specific gravity of 137 

Single-acting engines 64 

Single-acting pump 107 

Single riveting 53 

Slide valve, defined 1 ' 3 

Duties of 73 

Engine ; to reverse motion of 79 

To test for leaks 77 

Slippage 114 

Smoke fThe), problem 160 

Solid-brace 30 

Soot, effect on the Interior of boilers 36 

South pole of electro-magnet 131 

Special report of N. Y. Bureau 203 

Specific heat, definition and table 153 

Specific gravity, table 137 

Speed of escaping steam and water 118 

Speed ; regularity of , 70 

Spring ; number of an indicator 133 

Standard of cold production 143 

Starting an engine 78 

Stationary boilers ; kinds of 38 

Engines 65 

Stays ; boiler 190 

Riveting of gusset stays 34 

Steam. ; Boilers, description 21 

Boiler ; horizontal tubular 38 

" Breathing " of 34 

Cause of explosion 41 

F.ffect of heat on strength of 58 

Fixtures ; list of 83 

Fulcring 53 

Horse power of ; rule 140 

How to calculate strength of, with, example 57 

flow to calculate the force of expansion and con- 
traction -•• 38 



220 HAWKINS' AIDS. 



Steam Boiler; How to prepare for inspection 198 

Inspection ; N. Y. City report 203 

Inspection ; Brooklyn, N. Y., report 200 

Laws relating to the inspection of 197 

Locomotive 40 

Marine 40 

Method of testing 54 

Overstraining of 34 

Principal kinds 38 

Questions and answers relating to 53 

Stationary 88 

To calculate strength of seam 56 

Tube plate of 55 

Water tube 39 

Steam ; absolute pi essure of 63 

Dead 59 

Dry 59 

Dry ; as a conductor 104 

Expansion under pressure 60 

Gain in expansion 104 

Heating ; Questions and answers relating to 157 

Heating and ventilation 155 

How to generate, at 212° F 102 

Invisibility of 50 

Live 59 

Of what formed 121 

Physical properties of 59 

Repellant quality of particles of 63 

Saturated 59 

Saturated ; Tables 98-99 

Superheated 61 

Total heat of 103 

"Weight of .0 61 

Wet 63 

Wire drawing of 63 

Steam-end of a pump 107 

Engine 64 

Engines ; questions and answers 67 

Generators, principal kinds 38 

Injectors ; questions and answers relating to 117 

Jacket 104 

Line 131 

Pipe covering ; importance of 158 

Pipe ; how to estimate the safe working pressure 86 

Pipe ; tensile strength of 87 

Pipe ; how to estimate the diameter of 86 

Pipe ; how to estimate the size of 114 

Pipe ; Threads of 87 

Pumps ; direct acting Ill 

Valves ; how to connect 86 

Steamer " Northwest," description of engines 81 

Steel, definition 25 

Difference between, and iron 25 

Specific heat of - , 153 

Specific gravity of 137 

Tensile strength of 25 

Strain and stress defined 135 

Strength of riveted seam 56 

Steam boilers 53 

Stress and strain defined 135 

Stress carried by boiler stays, example 33 



INDEX. 221 

Stuffing-box, definition 76 

Submerged condenser, defined 146 

Subtraction of decimals 168 

Suction chamber 110 

Suction lift of a pump 108 

Suction pipes, what they should be provided with , ill 

Sulphur ; specific gravity of 137 

Summary of arithmetic ... 166 

Switch ; definition of a , 132 

Table of heat of combustion 50 

Mean pressures when cutting off 80 

Number of indicator spring 123 

Properties of saturated steam 98-99 

Specific heat 153 

Specific gravities 137 

Taking charge of anew engine 88 

Tensile strength defi ned 135 

Testing boilers ; method of 54 

Thermometer ; Centigrade, description 152 

Description 152 

Fahrenheit's 152 

Thimbles for boilers 83 

Third assistant engineers 189 

Three ; Rule of 170 

Three-way cock 85 

Throttle valve 85 

Throttling engines 68 

Through braces .30 

Time ; unit of. 154 

Tin, specific gravity 137 

Tortional strength 135 

Total heat of steam 102 

" Tough " metal 23 

Transverse strength defined 135 

Triple expansion engines 81 

Tube plate, defined 55 

T. U. (thermal unit) 108 

Unit of arithmetical calculations 154 

Heat 151,154 

Pressure 154 

Time 154 

Work 154 

U. S. Government rules for the safety valve 182 

Vacuum 73 

Valve ; definition of a . , 84, 108 

Valves of Corliss engines ; how to set 174 

Valve ; relief, back pressure, ball, three-way, cock, check, throt- 
tle, reducing, etc 85 

Valve spindle 90 

Ventilation ; heating and 155 

Latest idea relating to 159 

Questions and answers relating to 157 

Water and steam, as shown by diagram 124 

Cohesion of 63 

Composition of 116 

Circulation in boilers 47 

Cvlinder ; capacity of 113 

End of a pump 107 

Gauges 42 

la the cylinder ; effect of 74 

Specific heat of 153 



323 USTDEX. 

Water Standard for specific gravity 134 

Tube boilers, good and bad points 39 

Weakness in boilers ; cause of 41 

Weight for given safety valve to blow at given pressure 183 

Weight ; relative, of steam, water and air 61 

Weights ; measures and 154 

Weldable metal 23 

Wet steam =. 63 

Wiredrawing • 63 

Wood, lbs. of water evaporated from and at 212° 50 

Units of heat of combustion 50 

Work ; beat and 150 

Unit of 154 

Units of, as units of heat. ..... 1^^ 



LIST. 

!. 
Hawkins' New Catechism of Electricity, price post-paid, $2.00 

II. 
Hawkins' Aids to Engineers' Examinations, price post- 
paid, . 2.00 

(with Questions and Answers.) 
111. 

Hawkins' Maxims and Instructions for the Boiler Room, 

price post-paid, - - - - - - 2.00 

IV. 
Hawkins' Hand Book of Calculations for Engineers, price 

post-paid, - - - - - - - 2.00 

V. 
Hawkins' New Catechism of the Steam Engine, price 

post-paid, - 2.C0 

VI. 

Hawkins' Indicator Catechism (a practical treatise), price 

post-paid, ....... \QQ 



Each volume is provided with a carefully arranged refer- 
ence index, which places at ready commaud the information 
contained in the book upon any special subject upon which 
immediate help is needed. 




New 
Catechism 

of 
Electricity. 

A 

Practical 

Treatise 

Price, $2. 



This volume contains 550 pages of valuable informa- 
tion, 300 diagrams and illustrations, handsomely 
bound in heavy red leather, with gold edges, making 
a handy pocket companion, replete with invaluable 
knowledge; size 41^ x 6]/^ inches. 

This book has been issued in response to a real 
demand for a plain and practical treatise on the care 
and management of electrical plants and apparatus — 
a book to aid the average man, rather than the invent- 
or or experimenter in this all-alive matter. 

Hence the work will be found to be most complete 
ia this particular direction, containing all the. (book) 
information necessary for an experienced man to take 
charge of a dynamo or plant of any size. 

So important is the subject matter of this admirable 
work that there is only one time to order it and that is 
N0\\ . 



CONTENTS. 



The Dynamo; Conductors and Non-Conductors ; 
Symbols, abbreviations and definitions relating to 
electricity; Parts of the Dynamo; The Motor; The 
Care and Management of the Dynamo and Motor. 

Electric Lighting; Wiring; The rules and require- 
ments of the National Board of Underwriters in full; 
Electrical Measurements. 

The Electric Railway; Line Work; Instruction and 
Cautions for Linemen and the Dynamo Room ; Storage 
Batteries; Care and Management of tlie Street Car 
Motor; Electro Plating. 

The Telephone and Telegraph; The Electric Eleva- 
tor; Accidents and Emergencies, etc., etc. 

The full one-third part of the whole work has been 
devoted to the explanation and illustrations of the 
dynamo, and particular directions relating to its care 
and management; — all the directions are given in the 
simplest and most kindly way to assist rather than 
confuse the learner. The names of the various parts 
of the machine are also given with pictorial illustra- 
tions of the same. 

In the Catechism no less than 25 full page illustra- 
tions have been given of the various dynamo machines 
made in different parts of the country, and an equal 
number of part page illustrations. 




Questions 



s 



Engineers. 



This volume has over 2do pages of practical "pointers" 
showing the path of advancement, so much desired by aspiring 
engineers and firemen. It is printed on excellent paper and 
handsomely bound in heavy red leather, with gold title and 
edges. It is strongly bound for continuous study ; the size is 
5 X ■]%.. 

The work is a most important aid to all engineers, and 
is undoubtedly the most helpful ever issued relating to a safe 
and sure preparation for examination. 

It presents in a condensed form the most approved prac- 
tice in the care and management of Steam Boilers, Engines, 
Pumps, Electrical and Refrigerating Machines. 

On the following page is a list of its "helpful" contents. 



CONTENTvS 



This book embraces information not elsewhere obtainable. 

It tells exactly what an engineer will have to go through 
in getting a license, with much kindly and helpful advice to 
the applicant for a license. 

It contains the annual report of the superintendents of 
"Steam Boiler Inspection and Certification of Engineers" for 
the cities of New York and Brooklyn. 

It contains various rules, regulations and laws of cities 
for the examination of boilers and the licensing of engineers. 

It contains the laws and regulations of the United States 
for the examination and grading of all marine engineers. 

It gives a short chapter on the "Key to Success" in 
obtaining knowledge necessary for advancement in engineering. 
This is very important. 

The book gives the underlying principles of steam engineer- 
ing in plain language, with sample questions and answers 
likely to be asked by the examiner. 

It gives a few plain rules of arithmetic with examples of 
how to work the problems relating to the safety valve, strength 
of boilers and horse power of the Steam Engine and Steam 
Boiler. 

The main subjects treated, upon which are given detailed 
information with questions and answers, are as follows: — 
The Steam Boiler, Boiler Braces, Incrustation and Scale, 
Firing of Steam Boilers, "Water Circulation in Boilers, Con- 
struction and Strength of Boilers, The Steam Engine, Engine 
and Boiler Fittings, Pumps, The Injector, Electricity and 
Electric Machines, Steam Heating, Refrigeration, Valve 
Setting, etc. , etc. 




Maxims 

and 

Instructions 

for the 

Boiler Room 

Price, $2. 



This is, of all the Hawkins books, perhaps the 
most useful to the Engineer-in-charge, to the Fireman, 
to the Steam user or owner, and to the student of 
Steam Engineering. 

It is uniform in binding and size with ** Calcula- 
tions for Engineers " and the "New Catechism of the 
Steam Engine"; the size is 6xS}( inches, i}( inches 
thick; weight 2 lbs. ; it is bound in green silk cloth, 
gilt top and titles in gold; it has 331 pages with 185 
diagrams and illustrations. 

See next page for further particulars relating to 
the practical subjects embraced in this valuable 

volume. 



conte:nt^ 



Materials; Evaporation; Fire Irons and Tools; 
Firing of Steam Boilers; Points relating to Fuels; 
Foaming; Chapter of Don'ts ; Full descriptions of the 
Locomotive, Upright, Water Tube, Horizontal, and 
Marine Steam Boilers, Parts of a Boiler; Various 
Specifications for Construction of a Boiler; Riveting; 
Bracing; Various Repairs; Grate Bars; Boiler 
Cleaners; Boiler Scales; Boiler Tests; Scumming; 
Chemical Terms; Inspection of Boilers; Mechanical 
Stokers; Pumping Machinery ; Feed Water Heaters; 
Steam Heating; Plumbing; Safety Valve Rules. 

And many hundreds of other valuable pointers 
for Steam Users, Superintendents, Engineers, etc. 

No Engineer, Fireman or Steam User can afford 
to be without this valuable book, as it contains tht, 
pith and vital " points " of economical and safe steam 
production. 

The plan followed in this work is the same as 
that so generally approved in "Calculations"; it 
proceeds from the most simple rules and maxims to 
the highest problems; it is both a book of instruction 
and reference. The carefully prepared Index con- 
tains nearly one thousand references, thus making it 
almost a dictionary of terms. 







Engineers. 
Price $2. 



The work comprises the elements of Arithmetic, Mensura- 
tion, Geometr}', Mechanical Philosophy, with copious notes, 
explanations and help rules useful to an Engineer. 

And for reference, tables of squares and cubes, square and 
cube roots, circumference and areas of circles, tables of weights 
of metals and pipes, tables of pressures of steam, etc., etc. 

This is a work of instruction and reference relating to the 
steam engine, the steam boiler, etc , and has been said to con- 
tain every calculation, rule and table necessary to be known by 
the Engineer, Fireman and steam user. 

It is thus a complete course in Mathematics for the Engineer 
and steam user ; all calculations are in plain arithmetical 
figures, so the average man need not be confused by the inser- 
tion of the terms, symbols and characters to be found in works 
of " higher mathematics," so-called, yet the book is a complete 
treatise. 

It is bound uniform with the " New Catechism of the Steam 
Engine" and the "Instructions for the Boiler Room" (size 
6 X S3/( inches, weight 2 lbs. ) ; in green silk cloth ; printed on 
heavy, fine surface paper ; gold titles, gilt top ; with 330 pages 
and 150 illustrations. 



CONTENTS. 



Mechanical Powers; Natural or Mechanical Philos- 
ophy; Strength of Materials; Mensuration; Arith- 
metic ; Description of Algebra and Geometry ; Tables 
of Weights, Measures, Strength of Rope and Chains, 
Pressures of Water, Diameter of Pipes, etc. ; The 
Indicator, How to Compute; The Safety Valve, How 
to Figure; The Steam Boiler; The Steam Pump; 
Horse Powers, How to Figure for Engines and 
Boilers; Steam. What It Is, etc.; Index and Useful 
Definitions. 



" I am pleased with the work ; it is of 
value to nie. I have charge of a Harris- 
Corliss engine doing 680 H. P. at Slater's 
Cotton Mills."— Cyrus Bucki<in, Paw- 
tucket, R. I. 

"I think it the best T ever saw, and I 
thank the day I saw it advertised." — 
Jno. C. Robinson, Adams, Mass. 

"The Hand Book is worth its weight in 
dollars to any engineer with common 
sense."— J AS. C. Temple, Eng., Spring- 
field, 111. 




NEW 
CATECHISM 

OF THE : 
STEAMENGIi 



New 
Catechism 

of the 

Steam 
Engine. 

Price, $2. 



This is a rarely fine book, handsomely bound, in 
green silk cloth, gilt top, titles in gold; 440 pages; 
325 illustrations; size 6x8^ inches, i}( inches thick; 
weight 2 lbs. It is bound uniform in style and size.; 
with the "Hand Book of Calculations" and "Maxims 
and Instructions for the Boiler Room. " 

This will prove a valuable book both for study and 
reference, being finely illustrated and indexed. 

This work is gotten up to fill a long-felt need for a 
practical book. It gives directions for running the 
various types of steam engines that are to-day in the 
market. A list of subjects which are fully yet con- 
cisely discussed are found on the next page. 



CONTENTvS. 



The subject matter of the New Catechism of the 
Steam Engine is not arranged in chapters, but accord 
ing to the more natural order best designed to explain 
at greater or less length the different themes discussed. 
The following are the leading divisions of the 480 
pages of the book: 

Introduction; The Steam Engine; Historical Facts 
Relating to the Steam Engine; Engine Foundations; 
The Steam Piston; Connecting Rods; Eccentric; 
Governor ; Materials ; Workmanship ; Care and 
Management; Lining up a Horizontal or Vertical 
Engine; Lining Shafting; Valve Setting; Condensers ; 
Steam Separators ; Air, Gas and Compressing Engines ; 
Compounding; Arithmetic of the Steam Engine; 
Theory of the Steam Engine; Construction. 

There is also a description of numerous types of 
the engines now in operation, such as the Corliss, 
Westinghouse, etc. 

The book also treats generously upon the Marine, 
Locomotive and Gas Engines. 




Indicator 
Catechism 



Price, $1. 



This is a new book on an important subject. It is designed 
to thoroughly instruct the buyer upon the practical use of the 
Indicator, the Planimeter, the Pantagraph, Reducing Motions, 
etc. It contains nearly 200 pages with 1 15 valuable illustrations 
and diagrams, with questions and answers. 

CONTENTS.— Preparing Indicator for Use; Reducing 
Motions ; Piping up Indicator ; Taking Indicator Cards ; The 
Diagram ; Figuring Steam Consumption by the Diagram ; 
Revolution Counters ; Examples of Diagrams ; Description 
of Indicators ; Measuring Diagram by Ordinates ; Planimeters ; 
Pantagraphs, Tables, etc. 

The book is handsomely bound in silk (red) cloth, gilt edges, 
gold titles ; it is 5)4 x S){ inches and weighs 1}^ lbs. 



EASY PAYMENT OFFER. 



The Hawkins' Works are sold on easy payments; 
the set, six volames, price $i i.oo, will be sent express 
prepaid to any address upon receipt of $i.oo, and 
agreement to pay balance in monthly installments of 
|!i.oo Each volume is complete in itself; one, two 
three, four or five books of the series will be sent on 
the easy terms, that is one dollar with order and the 
remainder of the purchase money $i.oo monthly. 



HCW TO OF.DER. 

With this pamphlet is sent a blank form ready for 
signing, and a return envelope; these are for con- 
venience, and not necessary to be used, as a simple 
order enclosing $i.oo and an agreement to send 
balance, $i.oo per month, will be sufficient. 



PUBI^ISHEI^S' GUARANTEE. 



The Publishers agree that if the books are not all 
that they are claimed to be, they can be returned and 
the money paid will be returned to the purchaser. 



PERSONAL STATEMENT. 

In ordering it is kindly requested that our patrons 
send one or two names of whom inquiry can be made, 
if desired — the question being — "Is the party good 
for what he agrees?" But! a simple statement as to 
position held will be sufficient. 



<o^ 






^ Directions.'^ 



All books are shipped to subscribers, post or express 
charges paid, upon receipt of order. 




Remittances can be sent by Post Office or Express 
Money Orders, payable to our order. 



^ 



